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Sample records for anthropogenic noise effects

  1. How anthropogenic noise affects foraging.

    PubMed

    Luo, Jinhong; Siemers, Björn M; Koselj, Klemen

    2015-09-01

    The influence of human activity on the biosphere is increasing. While direct damage (e.g. habitat destruction) is relatively well understood, many activities affect wildlife in less apparent ways. Here, we investigate how anthropogenic noise impairs foraging, which has direct consequences for animal survival and reproductive success. Noise can disturb foraging via several mechanisms that may operate simultaneously, and thus, their effects could not be disentangled hitherto. We developed a diagnostic framework that can be applied to identify the potential mechanisms of disturbance in any species capable of detecting the noise. We tested this framework using Daubenton's bats, which find prey by echolocation. We found that traffic noise reduced foraging efficiency in most bats. Unexpectedly, this effect was present even if the playback noise did not overlap in frequency with the prey echoes. Neither overlapping noise nor nonoverlapping noise influenced the search effort required for a successful prey capture. Hence, noise did not mask prey echoes or reduce the attention of bats. Instead, noise acted as an aversive stimulus that caused avoidance response, thereby reducing foraging efficiency. We conclude that conservation policies may seriously underestimate numbers of species affected and the multilevel effects on animal fitness, if the mechanisms of disturbance are not considered.

  2. Experimental evidence for the effects of chronic anthropogenic noise on abundance of Greater Sage-Grouse at leks.

    PubMed

    Blickley, Jessica L; Blackwood, Diane; Patricelli, Gail L

    2012-06-01

    Increasing evidence suggests that chronic noise from human activities negatively affects wild animals, but most studies have failed to separate the effects of chronic noise from confounding factors, such as habitat fragmentation. We played back recorded continuous and intermittent anthropogenic sounds associated with natural gas drilling and roads at leks of Greater Sage-Grouse (Centrocercus urophasianus). For 3 breeding seasons, we monitored sage grouse abundance at leks with and without noise. Peak male attendance (i.e., abundance) at leks experimentally treated with noise from natural gas drilling and roads decreased 29% and 73%, respectively, relative to paired controls. Decreases in abundance at leks treated with noise occurred in the first year of the study and continued throughout the experiment. Noise playback did not have a cumulative effect over time on peak male attendance. There was limited evidence for an effect of noise playback on peak female attendance at leks or male attendance the year after the experiment ended. Our results suggest that sage-grouse avoid leks with anthropogenic noise and that intermittent noise has a greater effect on attendance than continuous noise. Our results highlight the threat of anthropogenic noise to population viability for this and other sensitive species. ©2012 Society for Conservation Biology.

  3. Are torpid bats immune to anthropogenic noise?

    PubMed

    Luo, Jinhong; Clarin, B-Markus; Borissov, Ivailo M; Siemers, Björn M

    2014-04-01

    Anthropogenic noise has a negative impact on a variety of animals. However, many bat species roost in places with high levels of anthropogenic noise. Here, we tested the hypothesis that torpid bats are insensitive to anthropogenic noise. In a laboratory experiment, we recorded skin temperature (Tsk) of bats roosting individually that were subjected to playbacks of different types of noise. We found that torpid bats with Tsk ~10°C lower than their active Tsk responded to all types of noise by elevating Tsk. Bats responded most strongly to colony and vegetation noise, and most weakly to traffic noise. The time of day when torpid bats were exposed to noise had a pronounced effect on responses. Torpid bats showed increasing responses from morning towards evening, i.e. towards the onset of the active phase. Skin temperature at the onset of noise exposure (Tsk,start, 17-29°C) was not related to the response. Moreover, we found evidence that torpid bats rapidly habituated to repeated and prolonged noise exposure.

  4. Predicting Anthropogenic Noise Contributions to US Waters.

    PubMed

    Gedamke, Jason; Ferguson, Megan; Harrison, Jolie; Hatch, Leila; Henderson, Laurel; Porter, Michael B; Southall, Brandon L; Van Parijs, Sofie

    2016-01-01

    To increase understanding of the potential effects of chronic underwater noise in US waters, the National Oceanic and Atmospheric Administration (NOAA) organized two working groups in 2011, collectively called "CetSound," to develop tools to map the density and distribution of cetaceans (CetMap) and predict the contribution of human activities to underwater noise (SoundMap). The SoundMap effort utilized data on density, distribution, acoustic signatures of dominant noise sources, and environmental descriptors to map estimated temporal, spatial, and spectral contributions to background noise. These predicted soundscapes are an initial step toward assessing chronic anthropogenic noise impacts on the ocean's varied acoustic habitats and the animals utilizing them.

  5. Anthropogenic noise affects behavior across sensory modalities.

    PubMed

    Kunc, Hansjoerg P; Lyons, Gillian N; Sigwart, Julia D; McLaughlin, Kirsty E; Houghton, Jonathan D R

    2014-10-01

    Many species are currently experiencing anthropogenically driven environmental changes. Among these changes, increasing noise levels are specifically a problem for species using acoustic signals (i.e., species relying on signals that use the same sensory modality as anthropogenic noise). Yet many species use other sensory modalities, such as visual and olfactory signals, to communicate. However, we have only little understanding of whether changes in the acoustic environment affect species that use sensory modalities other than acoustic signals. We studied the impact of anthropogenic noise on the common cuttlefish Sepia officinalis, which uses highly complex visual signals. We showed that cuttlefish adjusted their visual displays by changing their color more frequently during a playback of anthropogenic noise, compared with before and after the playback. Our results provide experimental evidence that anthropogenic noise has a marked effect on the behavior of species that are not reliant on acoustic communication. Thus, interference in one sensory channel, in this case the acoustic one, affects signaling in other sensory channels. By considering sensory channels in isolation, we risk overlooking the broader implications of environmental changes for the behavior of animals.

  6. Anthropogenic noise affects vocal interactions.

    PubMed

    McMullen, Heather; Schmidt, Rouven; Kunc, Hansjoerg P

    2014-03-01

    Animal communication plays a crucial role in many species, and it involves a sender producing a signal and a receiver responding to that signal. The shape of a signal is determined by selection pressures acting upon it. One factor that exerts selection on acoustic signals is the acoustic environment through which the signal is transmitted. Recent experimental studies clearly show that senders adjust their signals in response to increased levels of anthropogenic noise. However, to understand how noise affects the whole process of communication, it is vital to know how noise affects the receiver's response during vocal interactions. Therefore, we experimentally manipulated ambient noise levels to expose male European robins (Erithacus rubecula) to two playback treatments consisting of the same song: one with noise and another one without noise. We found that males responding to a conspecific in a noise polluted environment increased minimum frequency and decreased song complexity and song duration. Thus, we show that the whole process of communication is affected by noise, not just the behaviour of the sender.

  7. Anthropogenic noise changes arthropod abundances.

    PubMed

    Bunkley, Jessie P; McClure, Christopher J W; Kawahara, Akito Y; Francis, Clinton D; Barber, Jesse R

    2017-05-01

    Anthropogenic noise is a widespread and growing form of sensory pollution associated with the expansion of human infrastructure. One specific source of constant and intense noise is that produced by compressors used for the extraction and transportation of natural gas. Terrestrial arthropods play a central role in many ecosystems, and given that numerous species rely upon airborne sounds and substrate-borne vibrations in their life histories, we predicted that increased background sound levels or the presence of compressor noise would influence their distributions. In the second largest natural gas field in the United States (San Juan Basin, New Mexico, USA), we assessed differences in the abundances of terrestrial arthropod families and community structure as a function of compressor noise and background sound level. Using pitfall traps, we simultaneously sampled five sites adjacent to well pads that possessed operating compressors, and five alternate, quieter well pad sites that lacked compressors, but were otherwise similar. We found a negative association between sites with compressor noise or higher levels of background sound and the abundance of five arthropod families and one genus, a positive relationship between loud sites and the abundance of one family, and no relationship between noise level or compressor presence and abundance for six families and two genera. Despite these changes, we found no evidence of community turnover as a function of background sound level or site type (compressor and noncompressor). Our results indicate that anthropogenic noise differentially affects the abundances of some arthropod families. These preliminary findings point to a need to determine the direct and indirect mechanisms driving these observed responses. Given the diverse and important ecological functions provided by arthropods, changes in abundances could have ecological implications. Therefore, we recommend the consideration of arthropods in the environmental

  8. Anthropogenic noise increases fish mortality by predation

    PubMed Central

    Simpson, Stephen D.; Radford, Andrew N.; Nedelec, Sophie L.; Ferrari, Maud C. O.; Chivers, Douglas P.; McCormick, Mark I.; Meekan, Mark G.

    2016-01-01

    Noise-generating human activities affect hearing, communication and movement in terrestrial and aquatic animals, but direct evidence for impacts on survival is rare. We examined effects of motorboat noise on post-settlement survival and physiology of a prey fish species and its performance when exposed to predators. Both playback of motorboat noise and direct disturbance by motorboats elevated metabolic rate in Ambon damselfish (Pomacentrus amboinensis), which when stressed by motorboat noise responded less often and less rapidly to simulated predatory strikes. Prey were captured more readily by their natural predator (dusky dottyback, Pseudochromis fuscus) during exposure to motorboat noise compared with ambient conditions, and more than twice as many prey were consumed by the predator in field experiments when motorboats were passing. Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans. PMID:26847493

  9. Anthropogenic noise increases fish mortality by predation.

    PubMed

    Simpson, Stephen D; Radford, Andrew N; Nedelec, Sophie L; Ferrari, Maud C O; Chivers, Douglas P; McCormick, Mark I; Meekan, Mark G

    2016-02-05

    Noise-generating human activities affect hearing, communication and movement in terrestrial and aquatic animals, but direct evidence for impacts on survival is rare. We examined effects of motorboat noise on post-settlement survival and physiology of a prey fish species and its performance when exposed to predators. Both playback of motorboat noise and direct disturbance by motorboats elevated metabolic rate in Ambon damselfish (Pomacentrus amboinensis), which when stressed by motorboat noise responded less often and less rapidly to simulated predatory strikes. Prey were captured more readily by their natural predator (dusky dottyback, Pseudochromis fuscus) during exposure to motorboat noise compared with ambient conditions, and more than twice as many prey were consumed by the predator in field experiments when motorboats were passing. Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans.

  10. Impact of Anthropogenic Noise on Aquatic Animals: From Single Species to Community-Level Effects.

    PubMed

    Sabet, Saeed Shafiei; Neo, Yik Yaw; Slabbekoorn, Hans

    2016-01-01

    Anthropogenic noise underwater is on the rise and may affect aquatic animals of marine and freshwater ecosystems. Many recent studies concern some sort of impact assessment of a single species. Few studies addressed the noise impact on species interactions underwater, whereas there are some studies that address community-level impact but only on land in air. Key processes such as predator-prey or competitor interactions may be affected by the masking of auditory cues, noise-related disturbance, or attentional interference. Noise-associated changes in these interactions can cause shifts in species abundance and modify communities, leading to fundamental ecosystem changes. To gain further insight into the mechanism and generality of earlier findings, we investigated the impact on both a predator and a prey species in captivity, zebrafish (Danio rerio) preying on waterfleas (Daphnia magna).

  11. Peer-Reviewed Studies on the Effects of Anthropogenic Noise on Marine Invertebrates: From Scallop Larvae to Giant Squid.

    PubMed

    de Soto, Natacha Aguilar

    2016-01-01

    Marine invertebrates at the base of oceanic trophic webs play important ecological and economical roles supporting worldwide fisheries worth millions. There is an increasing concern about the effects of anthropogenic noise on marine fauna but little is known about its effects on invertebrates. Here the current peer-reviewed literature on this subject is reviewed, dealing with different ontogenetic stages and taxa. These studies show that the noise effects on marine invertebrates range from apparently null to behavioral/physiological responses to mortalities. They emphasize the need to consider potential interactions of human activities using intense sound sources with the conservation and fisheries of local invertebrate stocks.

  12. Blue whales respond to anthropogenic noise.

    PubMed

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  13. Blue Whales Respond to Anthropogenic Noise

    PubMed Central

    Melcón, Mariana L.; Cummins, Amanda J.; Kerosky, Sara M.; Roche, Lauren K.; Wiggins, Sean M.; Hildebrand, John A.

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood. PMID:22393434

  14. Anthropogenic noise disrupts use of vocal information about predation risk.

    PubMed

    Kern, Julie M; Radford, Andrew N

    2016-11-01

    Anthropogenic noise is rapidly becoming a universal environmental feature. While the impacts of such additional noise on avian sexual signals are well documented, our understanding of its effect in other terrestrial taxa, on other vocalisations, and on receivers is more limited. Little is known, for example, about the influence of anthropogenic noise on responses to vocalisations relating to predation risk, despite the potential fitness consequences. We use playback experiments to investigate the impact of traffic noise on the responses of foraging dwarf mongooses (Helogale parvula) to surveillance calls produced by sentinels, individuals scanning for danger from a raised position whose presence usually results in reduced vigilance by foragers. Foragers exhibited a lessened response to surveillance calls in traffic-noise compared to ambient-sound playback, increasing personal vigilance. A second playback experiment, using noise playbacks without surveillance calls, suggests that the increased vigilance could arise in part from the direct influence of additional noise as there was an increase in response to traffic-noise playback alone. Acoustic masking could also play a role. Foragers maintained the ability to distinguish between sentinels of different dominance class, increasing personal vigilance when presented with subordinate surveillance calls compared to calls of a dominant groupmate in both noise treatments, suggesting complete masking was not occurring. However, an acoustic-transmission experiment showed that while surveillance calls were potentially audible during approaching traffic noise, they were probably inaudible during peak traffic intensity noise. While recent work has demonstrated detrimental effects of anthropogenic noise on defensive responses to actual predatory attacks, which are relatively rare, our results provide evidence of a potentially more widespread influence since animals should constantly assess background risk to optimise the

  15. The sperm whale sonar: Monitoring and use in mitigation of anthropogenic noise effects in the marine environment

    NASA Astrophysics Data System (ADS)

    André, Michel

    2009-04-01

    Noise pollution in the marine environment is an emerging but serious concern. Its implications are less well understood than other global threats and largely undetectable to everyone but the specialist. In addition, the assessment of the acoustic impact of artificial sounds in the sea is not a trivial task, certainly because there is a lack of information on how the marine organisms process and analyse sounds and how relevant these sounds are for the balance and development of the populations. Further, this possible acoustic impact not only concerns the hearing systems but may also affect other sensory or systemic levels and result equally lethal for the animal concerned. If we add that the negative consequences of a short or long term exposure to artificial sounds may not be immediately observed one can understood how challenging it is to obtain objective data allowing an efficient control of the introduction of anthropogenic sound in the sea. To answer some of these questions, the choice to investigate cetaceans and their adaptation to an aquatic environment is not fortuitous. Cetaceans, because of their optimum use of sound as an ad-hoc source of energy and their almost exclusive dependence on acoustic information, represent not only the best bio-indicator of the effects of noise pollution in the marine environment, but also a source of data to improve and develop human underwater acoustic technology. Here, we present how the characteristics and performance of the sperm whale mid-range biosonar can be used to develop a mitigation solution based on passive acoustics and ambient noise imaging to prevent negative interactions with human activities by monitoring cetacean movements in areas of interest, e.g. deep-sea observatories.

  16. Cross-modal impacts of anthropogenic noise on information use.

    PubMed

    Morris-Drake, Amy; Kern, Julie M; Radford, Andrew N

    2016-10-24

    Anthropogenic noise is a global pollutant, and there is rapidly accumulating evidence of impacts on a range of animal taxa [1,2]. While many studies have considered how additional noise may affect information provision and use, they have focused on the masking and consequent alteration of acoustic signals and cues; so-called unimodal effects [3]. Using field-based experimental trials on habituated wild dwarf mongooses (Helogale parvula) [4], we combine sound playbacks and faecal presentations to demonstrate that anthropogenic noise can disrupt responses to information from different sensory modalities. The adaptive, stronger response exhibited towards predator faeces compared with control faeces in ambient-noise conditions was detrimentally affected by road-noise playback. Specifically, having taken longer to detect the faeces, the mongooses interacted less with the predator cue, did not show increased vigilance following its detection, and spent less time in the safe vicinity of a burrow refuge, thus suffering a potentially increased predation risk. Our results are the first to show that anthropogenic noise could alter responses to olfactory cues, strongly indicating the possibility of cross-modal impacts of noise pollution on information use [3]. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  17. Condition-dependent physiological and behavioural responses to anthropogenic noise.

    PubMed

    Purser, Julia; Bruintjes, Rick; Simpson, Stephen D; Radford, Andrew N

    2016-03-01

    Anthropogenic (man-made) noise, a global pollutant of international concern, is known to affect the physiology and behaviour of a range of organisms. However, experimental studies have tended to focus on trait means; intra-population variation in responses are likely, but have rarely been explored. Here we use established experimental methods to demonstrate a condition-dependent effect of additional noise. We show that juvenile European eels (Anguilla anguilla) in good condition do not respond differently to playbacks of ambient coastal noise and coastal noise with passing ships. By contrast, the additional noise of ship passes caused an increase in ventilation rate and a decrease in startling to a looming predatory stimulus in poor condition eels. Intra-population variation in responses to noise has important implications both for population dynamics and the planning of mitigation measures. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Anthropogenic noise affects song structure in red-winged blackbirds (Agelaius phoeniceus).

    PubMed

    Hanna, Dalal; Blouin-Demers, Gabriel; Wilson, David R; Mennill, Daniel J

    2011-11-01

    Anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. In response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals. These changes can be a short-term modification in response to transient noise or a long-term modification in response to chronic noise. An animal's ability to adapt to anthropogenic noise can be crucial to its success. In this study, we evaluated the effects of anthropogenic noise on the structure of red-winged blackbird song. First, we manipulated the presence of anthropogenic noise by experimentally broadcasting either silence or low-frequency white noise to subjects inhabiting quiet marshes located away from roadsides. Subjects exhibited increased signal tonality when temporarily exposed to low-frequency white noise, suggesting that red-winged blackbirds can alter their signals rapidly in response to sudden noise. Second, we compared songs produced in quiet marshes located away from roadsides with songs produced during quiet periods at roadside marshes that are normally noisy. This allowed us to test whether birds that are exposed to chronic anthropogenic noise exhibit altered song structure during temporarily quiet periods. Subjects residing in roadside marshes that are normally polluted with anthropogenic noise sang songs with increased tonality during quiet periods. Overall, our results show that anthropogenic noise influences the structure of birdsong. These effects should be considered in conservation and wildlife management.

  19. Potential Uses of Anthropogenic Noise as a Source of Information in Animal Sensory and Communication Systems.

    PubMed

    Stansbury, Amanda; Deecke, Volker; Götz, Thomas; Janik, Vincent M

    2016-01-01

    Although current research on the impact of anthropogenic noise has focused on the detrimental effects, there is a range of ways by which animals could benefit from increased noise levels. Here we discuss two potential uses of anthropogenic noise. First, local variations in the ambient-noise field could be used to perceive objects and navigate within an environment. Second, introduced sound cues could be used as a signal for prey detection or orientation and navigation. Although the disadvantages of noise pollution will likely outweigh any positive effects, it is important to acknowledge that such changes may benefit some species.

  20. Vocal traits and diet explain avian sensitivities to anthropogenic noise.

    PubMed

    Francis, Clinton D

    2015-05-01

    Global population growth has caused extensive human-induced environmental change, including a near-ubiquitous transformation of the acoustical environment due to the propagation of anthropogenic noise. Because the acoustical environment is a critical ecological dimension for countless species to obtain, interpret and respond to environmental cues, highly novel environmental acoustics have the potential to negatively impact organisms that use acoustics for a variety of functions, such as communication and predator/prey detection. Using a comparative approach with 308 populations of 183 bird species from 14 locations in Europe, North American and the Caribbean, I sought to reveal the intrinsic and extrinsic factors responsible for avian sensitivities to anthropogenic noise as measured by their habitat use in noisy versus adjacent quiet locations. Birds across all locations tended to avoid noisy areas, but trait-specific differences emerged. Vocal frequency, diet and foraging location predicted patterns of habitat use in response to anthropogenic noise, but body size, nest placement and type, other vocal features and the type of anthropogenic noise (chronic industrial vs. intermittent urban/traffic noise) failed to explain variation in habitat use. Strongly supported models also indicated the relationship between sensitivity to noise and predictive traits had little to no phylogenetic structure. In general, traits associated with hearing were strong predictors - species with low-frequency vocalizations, which experience greater spectral overlap with low-frequency anthropogenic noise tend to avoid noisy areas, whereas species with higher frequency vocalizations respond less severely. Additionally, omnivorous species and those with animal-based diets were more sensitive to noise than birds with plant-based diets, likely because noise may interfere with the use of audition in multimodal prey detection. Collectively, these results suggest that anthropogenic noise is a

  1. United States Bureau of Ocean Energy Management, Regulation and Enforcement: filling data gaps to better understand the effects of anthropogenic noise on marine life.

    PubMed

    Lewandowski, Jill; Burkhard, Elizabeth; Skrupky, Kimberly; Epperson, Deborah

    2012-01-01

    Protecting the environment while ensuring the safe development of our Nation's offshore energy(from both renewable and traditional sources) and marine mineral resources is a critical part of the mission of the BOEMRE. The BOEMRE, as with all federal agencies, must consider the potential environmental impacts for every decision made. This includes understanding the potential for and degree of adverse effects that may result from the introduction of anthropogenic noise into the marine environment from BOEMRE-regulated industry sources. The ESP and the TAR Program are integral in helping the BOEMRE achieve this mission because the strength and quality of the environmental decision making can only be as good as the science supporting it. Cumulatively,these research programs help the BOEMRE pursue an adaptive and ecosystem-based approach to its stewardship responsibilities.

  2. Anthropogenic noise alters dwarf mongoose responses to heterospecific alarm calls.

    PubMed

    Morris-Drake, Amy; Bracken, Anna M; Kern, Julie M; Radford, Andrew N

    2017-04-01

    Anthropogenic noise is an evolutionarily novel and widespread pollutant in both terrestrial and aquatic habitats. Despite increasing evidence that the additional noise generated by human activities can affect vocal communication, the majority of research has focused on the use of conspecific acoustic information, especially sexual signals. Many animals are known to eavesdrop on the alarm calls produced by other species, enhancing their likelihood of avoiding predation, but how this use of heterospecific information is affected by anthropogenic noise has received little empirical attention. Here, we use two field-based playback experiments on a habituated wild population of dwarf mongooses (Helogale parvula) to determine how anthropogenic noise influences the response of foragers to heterospecific alarm calls. We begin by demonstrating that dwarf mongooses respond appropriately to the alarm calls of sympatric chacma baboons (Papio ursinus) and tree squirrels (Paraxerus cepapi); fleeing only to the latter. We then show that mongoose foragers are less likely to exhibit this flee response to tree squirrel alarm calls during road-noise playback compared to ambient-sound playback. One explanation for the change in response is that noise-induced distraction or stress result in maladaptive behaviour. However, further analysis revealed that road-noise playback results in increased vigilance and that mongooses showing the greatest vigilance increase are those that do not subsequently exhibit a flee response to the alarm call. These individuals may therefore be acting appropriately: if the greater gathering of personal information indicates the absence of an actual predator despite an alarm call, the need to undertake costly fleeing behaviour can be avoided. Either way, our study indicates the potential for anthropogenic noise to interfere with the use of acoustic information from other species, and suggests the importance of considering how heterospecific networks are

  3. Anthropogenic noise compromises the anti-predator behaviour of the European seabass, Dicentrarchus labrax (L.).

    PubMed

    Spiga, Ilaria; Aldred, Nicholas; Caldwell, Gary S

    2017-09-15

    Anthropogenic noise is a significant pollutant of the world's oceans, affecting behavioural and physiological traits in a range of species, including anti-predator behaviours. Using the open field test, we investigated the effects of recordings of piling and drilling noise on the anti-predator behaviour of captive juvenile European seabass in response to a visual stimulus (a predatory mimic). The impulsive nature of piling noise triggered a reflexive startle response, which contrasted the behaviour elicited by the continuous drilling noise. When presented with the predatory mimic, fish exposed to both piling and drilling noise explored the experimental arena more extensively than control fish exposed to ambient noise. Fish under drilling and piling conditions also exhibited reduced predator inspection behaviour. Piling and drilling noise induced stress as measured by ventilation rate. This study provides further evidence that the behaviour and physiology of European seabass is significantly affected by exposure to elevated noise levels. Copyright © 2017. Published by Elsevier Ltd.

  4. Anthropogenic electromagnetic noise disrupts magnetic compass orientation in a migratory bird.

    PubMed

    Engels, Svenja; Schneider, Nils-Lasse; Lefeldt, Nele; Hein, Christine Maira; Zapka, Manuela; Michalik, Andreas; Elbers, Dana; Kittel, Achim; Hore, P J; Mouritsen, Henrik

    2014-05-15

    Electromagnetic noise is emitted everywhere humans use electronic devices. For decades, it has been hotly debated whether man-made electric and magnetic fields affect biological processes, including human health. So far, no putative effect of anthropogenic electromagnetic noise at intensities below the guidelines adopted by the World Health Organization has withstood the test of independent replication under truly blinded experimental conditions. No effect has therefore been widely accepted as scientifically proven. Here we show that migratory birds are unable to use their magnetic compass in the presence of urban electromagnetic noise. When European robins, Erithacus rubecula, were exposed to the background electromagnetic noise present in unscreened wooden huts at the University of Oldenburg campus, they could not orient using their magnetic compass. Their magnetic orientation capabilities reappeared in electrically grounded, aluminium-screened huts, which attenuated electromagnetic noise in the frequency range from 50 kHz to 5 MHz by approximately two orders of magnitude. When the grounding was removed or when broadband electromagnetic noise was deliberately generated inside the screened and grounded huts, the birds again lost their magnetic orientation capabilities. The disruptive effect of radiofrequency electromagnetic fields is not confined to a narrow frequency band and birds tested far from sources of electromagnetic noise required no screening to orient with their magnetic compass. These fully double-blinded tests document a reproducible effect of anthropogenic electromagnetic noise on the behaviour of an intact vertebrate.

  5. Does Anthropogenic Noise in National Parks Impair Memory?

    ERIC Educational Resources Information Center

    Benfield, Jacob A.; Bell, Paul A.; Troup, Lucy J.; Soderstrom, Nick

    2010-01-01

    Research on noise shows that a variety of effects including stress, annoyance, and performance decrements exist for certain types of sounds. Noise interferes with cognitive ability by overloading the attentional system or simply distracting from efficient encoding or rehearsal, but very little research has extended those findings to recreation or…

  6. Does Anthropogenic Noise in National Parks Impair Memory?

    ERIC Educational Resources Information Center

    Benfield, Jacob A.; Bell, Paul A.; Troup, Lucy J.; Soderstrom, Nick

    2010-01-01

    Research on noise shows that a variety of effects including stress, annoyance, and performance decrements exist for certain types of sounds. Noise interferes with cognitive ability by overloading the attentional system or simply distracting from efficient encoding or rehearsal, but very little research has extended those findings to recreation or…

  7. Natural and anthropogenic ocean noise recorded at long-term and temporary observatories

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Metz, Dirk; Watts, Anthony B.; Geissler, Wolfram

    2017-04-01

    Most people worldwide would assume that the oceans are silent. However, a number of natural phenomenon's like ocean waves, wind, lightening, ice noise, earthquakes, and submarine volcanic activity contributes to the ambient ocean noise. During their evolution, marine animals like fish and mammals have adopted in many ways to the acoustic properties of the sea. Yet in recent decades, anthropogenic and hence manmade ocean noise level has risen profoundly. Due to extreme reliance of fish and mammals on underwater sounds for basic life functions, including searching for food or mate and the absence of any mechanism to safeguard them against it, underwater noise pollution may disrupt marine life. The primary sources of low-frequency anthropogenic noise include sounds associated with shipping, military operations, oil and gas exploration and production, and even research activities. Some scientists suggest that today virtually no marine environment is without any noise pollution. Thus, all marine life forms that rely heavily on the integrity of their acoustic habitat may have to adapt to new conditions. Of greatest concern for whales are low-frequency sounds that travel long distances in the ocean. Ship propellers and motors, for instance, produce sound at low frequencies, as do natural and manmade seismic activity. These profound, loud noises reverberate in the deep ocean and can effectively mask or block vital whale communication. However, in general very little is known about the world-wide distribution of ambient ocean noise. Thus, on a global scale and considering the vast areas of the world's oceans, we know virtually nothing about noise levels in different parts of the oceans and how anthropogenic noise contributes to ambient noise. Here, we use hydrophone recordings from the UN's Comprehensive Nuclear-Test-Ban Treaty organization (CTBTO) and ocean-bottom seismometers to provide an assessment of noise in all major basins, including the Pacific, Atlantic and Indian

  8. Vocal frequency change reflects different responses to anthropogenic noise in two suboscine tyrant flycatchers

    PubMed Central

    Francis, Clinton D.; Ortega, Catherine P.; Cruz, Alexander

    2011-01-01

    Anthropogenic noise is prevalent across the globe and can exclude birds from otherwise suitable habitat and negatively influence fitness; however, the mechanisms responsible for species' responses to noise are not always clear. One effect of noise is a reduction in effective acoustic communication through acoustic masking, yet some urban songbirds may compensate for masking by noise through altering their songs. Whether this vocal flexibility accounts for species persistence in noisy areas is unknown. Here, we investigated the influence of noise on habitat use and vocal frequency in two suboscine flycatchers using a natural experiment that isolated effects of noise from confounding stimuli common to urban habitats. With increased noise exposure, grey flycatcher (Empidonax wrightii) occupancy declined, but vocal frequency did not change. By contrast, ash-throated flycatcher (Myiarchus cinerascens) occupancy was uninfluenced by noise, but individuals in areas with greater noise amplitudes vocalized at a higher frequency, although the increase (≈200 kHz) may only marginally improve communication and may represent a secondary effect from increased vocal amplitude. Even so, the different flycatcher behavioural responses suggest that signal change may help some species persist in noisy areas and prompt important questions regarding which species will cope with an increasingly noisy world. PMID:21123268

  9. Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate

    PubMed Central

    Nedelec, Sophie L.; Radford, Andrew N.; Simpson, Stephen D.; Nedelec, Brendan; Lecchini, David; Mills, Suzanne C.

    2014-01-01

    Human activities can create noise pollution and there is increasing international concern about how this may impact wildlife. There is evidence that anthropogenic noise may have detrimental effects on behaviour and physiology in many species but there are few examples of experiments showing how fitness may be directly affected. Here we use a split-brood, counterbalanced, field experiment to investigate the effect of repeated boat-noise playback during early life on the development and survival of a marine invertebrate, the sea hare Stylocheilus striatus at Moorea Island (French Polynesia). We found that exposure to boat-noise playback, compared to ambient-noise playback, reduced successful development of embryos by 21% and additionally increased mortality of recently hatched larvae by 22%. Our work, on an understudied but ecologically and socio-economically important taxon, demonstrates that anthropogenic noise can affect individual fitness. Fitness costs early in life have a fundamental influence on population dynamics and resilience, with potential implications for community structure and function. PMID:25080997

  10. Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate.

    PubMed

    Nedelec, Sophie L; Radford, Andrew N; Simpson, Stephen D; Nedelec, Brendan; Lecchini, David; Mills, Suzanne C

    2014-07-31

    Human activities can create noise pollution and there is increasing international concern about how this may impact wildlife. There is evidence that anthropogenic noise may have detrimental effects on behaviour and physiology in many species but there are few examples of experiments showing how fitness may be directly affected. Here we use a split-brood, counterbalanced, field experiment to investigate the effect of repeated boat-noise playback during early life on the development and survival of a marine invertebrate, the sea hare Stylocheilus striatus at Moorea Island (French Polynesia). We found that exposure to boat-noise playback, compared to ambient-noise playback, reduced successful development of embryos by 21% and additionally increased mortality of recently hatched larvae by 22%. Our work, on an understudied but ecologically and socio-economically important taxon, demonstrates that anthropogenic noise can affect individual fitness. Fitness costs early in life have a fundamental influence on population dynamics and resilience, with potential implications for community structure and function.

  11. Anthropogenic noise playback impairs embryonic development and increases mortality in a marine invertebrate

    NASA Astrophysics Data System (ADS)

    Nedelec, Sophie L.; Radford, Andrew N.; Simpson, Stephen D.; Nedelec, Brendan; Lecchini, David; Mills, Suzanne C.

    2014-07-01

    Human activities can create noise pollution and there is increasing international concern about how this may impact wildlife. There is evidence that anthropogenic noise may have detrimental effects on behaviour and physiology in many species but there are few examples of experiments showing how fitness may be directly affected. Here we use a split-brood, counterbalanced, field experiment to investigate the effect of repeated boat-noise playback during early life on the development and survival of a marine invertebrate, the sea hare Stylocheilus striatus at Moorea Island (French Polynesia). We found that exposure to boat-noise playback, compared to ambient-noise playback, reduced successful development of embryos by 21% and additionally increased mortality of recently hatched larvae by 22%. Our work, on an understudied but ecologically and socio-economically important taxon, demonstrates that anthropogenic noise can affect individual fitness. Fitness costs early in life have a fundamental influence on population dynamics and resilience, with potential implications for community structure and function.

  12. Anthropogenic noise is associated with reductions in the productivity of breeding Eastern Bluebirds (Sialia sialis).

    PubMed

    Kight, Caitlin R; Saha, Margaret S; Swaddle, John P

    2012-10-01

    Although previous studies have related variations in environmental noise levels with alterations in communication behaviors of birds, little work has investigated the potential long-term implications of living or breeding in noisy habitats. However, noise has the potential to reduce fitness, both directly (because it is a physiological stressor) and indirectly (by masking important vocalizations and/or leading to behavioral changes). Here, we quantified acoustic conditions in active breeding territories of male Eastern Bluebirds (Sialia sialis). Simultaneously, we measured four fitness indicators: cuckoldry rates, brood growth rate and condition, and number of fledglings produced (i.e., productivity). Increases in environmental noise tended to be associated with smaller brood sizes and were more strongly related to reductions in productivity. Although the mechanism responsible for these patterns is not yet clear, the breeding depression experienced by this otherwise disturbance-tolerant species indicates that anthropogenic noise may have damaging effects on individual fitness and, by extraction, the persistence of populations in noisy habitats. We suggest that managers might protect avian residents from potentially harmful noise by keeping acoustically dominant anthropogenic habitat features as far as possible from favored songbird breeding habitats, limiting noisy human activities, and/or altering habitat structure in order to minimize the propagation of noise pollution.

  13. Anthropogenic noise affects risk assessment and attention: the distracted prey hypothesis

    PubMed Central

    Chan, Alvin Aaden Yim-Hol; Giraldo-Perez, Paulina; Smith, Sonja; Blumstein, Daniel T.

    2010-01-01

    Many studies have focused on the effects of anthropogenic noise on animal communication, but only a few have looked at its effect on other behavioural systems. We designed a playback experiment to test the effect of noise on predation risk assessment. We found that in response to boat motor playback, Caribbean hermit crabs (Coenobita clypeatus) allowed a simulated predator to approach closer before they hid. Two hypotheses may explain how boat noise affected risk assessment: it masked an approaching predator's sound; and/or it reallocated some of the crabs' finite attention, effectively distracting them, and thus preventing them from responding to an approaching threat. We found no support for the first hypothesis: a silent looming object still got closer during boat motor playbacks than during silence. However, we found support for the attentional hypothesis: when we added flashing lights to the boat motor noise to further distract the hermit crabs, we were able to approach the crabs more closely than with the noise alone. Anthropogenic sounds may thus distract prey and make them more vulnerable to predation. PMID:20164080

  14. Anthropogenic noise affects risk assessment and attention: the distracted prey hypothesis.

    PubMed

    Chan, Alvin Aaden Yim-Hol; Giraldo-Perez, Paulina; Smith, Sonja; Blumstein, Daniel T

    2010-08-23

    Many studies have focused on the effects of anthropogenic noise on animal communication, but only a few have looked at its effect on other behavioural systems. We designed a playback experiment to test the effect of noise on predation risk assessment. We found that in response to boat motor playback, Caribbean hermit crabs (Coenobita clypeatus) allowed a simulated predator to approach closer before they hid. Two hypotheses may explain how boat noise affected risk assessment: it masked an approaching predator's sound; and/or it reallocated some of the crabs' finite attention, effectively distracting them, and thus preventing them from responding to an approaching threat. We found no support for the first hypothesis: a silent looming object still got closer during boat motor playbacks than during silence. However, we found support for the attentional hypothesis: when we added flashing lights to the boat motor noise to further distract the hermit crabs, we were able to approach the crabs more closely than with the noise alone. Anthropogenic sounds may thus distract prey and make them more vulnerable to predation.

  15. Anthropogenic noise causes body malformations and delays development in marine larvae.

    PubMed

    de Soto, Natacha Aguilar; Delorme, Natali; Atkins, John; Howard, Sunkita; Williams, James; Johnson, Mark

    2013-10-03

    Understanding the impact of noise on marine fauna at the population level requires knowledge about the vulnerability of different life-stages. Here we provide the first evidence that noise exposure during larval development produces body malformations in marine invertebrates. Scallop larvae exposed to playbacks of seismic pulses showed significant developmental delays and 46% developed body abnormalities. Similar effects were observed in all independent samples exposed to noise while no malformations were found in the control groups (4881 larvae examined). Malformations appeared in the D-veliger larval phase, perhaps due to the cumulative exposure attained by this stage or to a greater vulnerability of D-veliger to sound-mediated physiological or mechanical stress. Such strong impacts suggest that abnormalities and growth delays may also result from lower sound levels or discrete exposures during the D-stage, increasing the potential for routinely-occurring anthropogenic noise sources to affect recruitment of wild scallop larvae in natural stocks.

  16. Ecology of estuaries: Anthropogenic effects

    SciTech Connect

    Kennish, M.J.

    1992-01-01

    Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; radionuclides) biological impacts; waste management; impacts of power plants; dredging and spoil disposal; case studies, primarily Chesapeake Bay. The book serves as a text and as a reference.

  17. Birds and anthropogenic noise: singing higher may matter.

    PubMed

    Slabbekoorn, Hans; Yang, Xiao-Jing; Halfwerk, Wouter

    2012-07-01

    In a recent theoretical study, Nemeth and Brumm explored the effect of amplitude and frequency variation in birdsongs on signal transmission in forested and noisy urban environments. They argued that "increased song pitch might not be an adaptation" but "an epiphenomenon of urbanization." Here we address the validity of comparing the communication benefits of changes in amplitude and frequency to question the adaptive significance of "urban songs." We believe that their calculations actually confirm considerable high-frequency benefits under noisy urban conditions, between and within species. Hence, we conclude that noise-dependent frequency shifts in urban birds can be adaptive.

  18. Recreational boating traffic: a chronic source of anthropogenic noise in the Wilmington, North Carolina Intracoastal Waterway.

    PubMed

    Haviland-Howell, Genevieve; Frankel, Adam S; Powell, Christopher M; Bocconcelli, Alessandro; Herman, Russell L; Sayigh, Laela S

    2007-07-01

    The majority of attention on the impact of anthropogenic noise on marine mammals has focused on low-frequency episodic activities. Persistent sources of mid-frequency noise pollution are less well studied. To address this data gap, the contribution of 25 physical, biological and anthropogenic factors to the ambient noise levels in the Wilmington, North Carolina Intracoastal Waterway were analyzed using a principal components analysis and least squares regression. The total number of recreational vessels passing through the waterway per hour is the factor that had the single greatest influence on environmental noise levels. During times of high boat traffic, anthropogenic noise is continuous rather than episodic, and occurs at frequencies that are biologically relevant to bottlenose dolphins. As a daily part of resident bottlenose dolphins' acoustic environment, recreational boating traffic may represent a chronic source of acoustic harassment.

  19. Impacts of chronic anthropogenic noise from energy-sector activity on abundance of songbirds in the boreal forest.

    PubMed

    Bayne, Erin M; Habib, Lucas; Boutin, Stan

    2008-10-01

    The effects of human activities in forests are often examined in the context of habitat conversion. Changes in habitat structure and composition are also associated with increases in the activity of people with vehicles and equipment, which results in increases in anthropogenic noise. Anthropogenic noise may reduce habitat quality for many species, particularly those that rely on acoustic signals for communication. We compared the density and occupancy rate of forest passerines close to versus far from noise-generating compressor stations and noiseless well pads in the boreal forest of Alberta, Canada. Using distance-based sampling, we found that areas near noiseless energy facilities had a total passerine density 1.5 times higher than areas near noise-producing energy sites. The White-throated Sparrow (Zonotrichia albicollis), Yellow-rumped Warbler (Dendroica coronata), and Red-eyed Vireo (Vireo olivaceus) were less dense in noisy areas. We used repeat sampling to estimate occupancy rate for 23 additional species. Seven had lower conditional or unconditional occupancy rates near noise-generating facilities. One-third of the species examined showed patterns that supported the hypothesis that abundance is influenced by anthropogenic noise. An additional 4 species responded negatively to edge effects. To mitigate existing noise impacts on birds would require approximately $175 million. The merits of such an effort relative to other reclamation actions are discussed. Nevertheless, given the $100 billion energy-sector investment planned for the boreal forest in the next 10 years, including noise suppression technology at the outset of construction, makes noise mitigation a cost-effective best-management practice that might help conserve high-quality habitat for boreal birds.

  20. The importance of invertebrates when considering the impacts of anthropogenic noise.

    PubMed

    Morley, Erica L; Jones, Gareth; Radford, Andrew N

    2014-02-07

    Anthropogenic noise is now recognized as a major global pollutant. Rapidly burgeoning research has identified impacts on individual behaviour and physiology through to community disruption. To date, however, there has been an almost exclusive focus on vertebrates. Not only does their central role in food webs and in fulfilling ecosystem services make imperative our understanding of how invertebrates are impacted by all aspects of environmental change, but also many of their inherent characteristics provide opportunities to overcome common issues with the current anthropogenic noise literature. Here, we begin by explaining why invertebrates are likely to be affected by anthropogenic noise, briefly reviewing their capacity for hearing and providing evidence that they are capable of evolutionary adaptation and behavioural plasticity in response to natural noise sources. We then discuss the importance of quantifying accurately and fully both auditory ability and noise content, emphasizing considerations of direct relevance to how invertebrates detect sounds. We showcase how studying invertebrates can help with the behavioural bias in the literature, the difficulties in drawing strong, ecologically valid conclusions and the need for studies on fitness impacts. Finally, we suggest avenues of future research using invertebrates that would advance our understanding of the impact of anthropogenic noise.

  1. The importance of invertebrates when considering the impacts of anthropogenic noise

    PubMed Central

    Morley, Erica L.; Jones, Gareth; Radford, Andrew N.

    2014-01-01

    Anthropogenic noise is now recognized as a major global pollutant. Rapidly burgeoning research has identified impacts on individual behaviour and physiology through to community disruption. To date, however, there has been an almost exclusive focus on vertebrates. Not only does their central role in food webs and in fulfilling ecosystem services make imperative our understanding of how invertebrates are impacted by all aspects of environmental change, but also many of their inherent characteristics provide opportunities to overcome common issues with the current anthropogenic noise literature. Here, we begin by explaining why invertebrates are likely to be affected by anthropogenic noise, briefly reviewing their capacity for hearing and providing evidence that they are capable of evolutionary adaptation and behavioural plasticity in response to natural noise sources. We then discuss the importance of quantifying accurately and fully both auditory ability and noise content, emphasizing considerations of direct relevance to how invertebrates detect sounds. We showcase how studying invertebrates can help with the behavioural bias in the literature, the difficulties in drawing strong, ecologically valid conclusions and the need for studies on fitness impacts. Finally, we suggest avenues of future research using invertebrates that would advance our understanding of the impact of anthropogenic noise. PMID:24335986

  2. Aviation noise effects

    NASA Astrophysics Data System (ADS)

    Newman, J. S.; Beattie, K. R.

    1985-03-01

    This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

  3. Auditory masking patterns in bottlenose dolphins (Tursiops truncatus) with natural, anthropogenic, and synthesized noise.

    PubMed

    Branstetter, Brian K; Trickey, Jennifer S; Bakhtiari, Kimberly; Black, Amy; Aihara, Hitomi; Finneran, James J

    2013-03-01

    Auditory masking occurs when one sound (usually called noise) interferes with the detection, discrimination, or recognition of another sound (usually called the signal). This interference can lead to detriments in a listener's ability to communicate, forage, and navigate. Most studies of auditory masking in marine mammals have been limited to detection thresholds of pure tones in Gaussian noise. Environmental noise marine mammals encounter is often more complex. In the current study, detection thresholds were estimated for bottlenose dolphins with a 10 kHz signal masked by natural, anthropogenic, and synthesized noise. Using a band-widening paradigm, detection thresholds exhibited a pattern where signal thresholds increased proportionally to bandwidth for narrow band noise. However, when noise bandwidth was greater than a critical band, masking patterns diverged. Subsequent experiments demonstrated that the auditory mechanisms responsible for the divergent masking patterns were related to across-channel comparison and within-valley listening.

  4. Applicability of Information Theory to the Quantification of Responses to Anthropogenic Noise by Southeast Alaskan Humpback Whales

    NASA Astrophysics Data System (ADS)

    Doyle, Laurance R.; McCowan, Brenda; Hanser, Sean F.; Chyba, Christopher; Bucci, Taylor; Blue, J. E.

    2008-06-01

    We assess the effectiveness of applying information theory to the characterization and quantification of the affects of anthropogenic vessel noise on humpback whale (Megaptera novaeangliae) vocal behavior in and around Glacier Bay, Alaska. Vessel noise has the potential to interfere with the complex vocal behavior of these humpback whales which could have direct consequences on their feeding behavior and thus ultimately on their health and reproduction. Humpback whale feeding calls recorded during conditions of high vessel-generated noise and lower levels of background noise are compared for differences in acoustic structure, use, and organization using information theoretic measures. We apply information theory in a self-referential manner (i.e., orders of entropy) to quantify the changes in signaling behavior. We then compare this with the reduction in channel capacity due to noise in Glacier Bay itself treating it as a (Gaussian) noisy channel. We find that high vessel noise is associated with an increase in the rate and repetitiveness of sequential use of feeding call types in our averaged sample of humpback whale vocalizations, indicating that vessel noise may be modifying the patterns of use of feeding calls by the endangered humpback whales in Southeast Alaska. The information theoretic approach suggested herein can make a reliable quantitative measure of such relationships and may also be adapted for wider application to many species where environmental noise is thought to be a problem.

  5. Different behavioural responses to anthropogenic noise by two closely related passerine birds

    PubMed Central

    Francis, Clinton D.; Ortega, Catherine P.; Cruz, Alexander

    2011-01-01

    Anthropogenic noise, now common to many landscapes, can impair acoustic communication for many species, yet some birds compensate for masking by noise by altering their songs. The phylogenetic distribution of these noise-dependent signal adjustments is uncertain, and it is not known whether closely related species respond similarly to noise. Here, we investigated the influence of noise on habitat occupancy rates and vocal frequency in two congeneric vireos with similar song features. Noise exposure did not influence occupancy rates for either species, yet song features of both changed, albeit in different ways. With increases in noise levels, plumbeous vireos (Vireo plumbeus) sang shorter songs with higher minimum frequencies. By contrast, grey vireos (Vireo vicinior) sang longer songs with higher maximum frequencies. These findings support the notion that vocal plasticity may help some species occupy noisy areas, but because there were no commonalities among the signal changes exhibited by these closely related birds, it may be difficult to predict how diverse species may modify their signals in an increasingly noisy world. PMID:21613284

  6. Quality of Green's Functions Improved by Automatic Detection and Removal of Coherent Anthropogenic Noise

    NASA Astrophysics Data System (ADS)

    Williams, E. F.; Martin, E. R.; Biondi, B. C.; Lindsey, N.; Ajo Franklin, J. B.; Wagner, A. M.; Bjella, K.; Daley, T. M.; Dou, S.; Freifeld, B. M.; Robertson, M.; Ulrich, C.

    2016-12-01

    We analyze the impact of identifying and removing coherent anthropogenic noise on synthetic Green's functions extracted from ambient noise recorded on a dense linear distributed acoustic sensing (DAS) array. Low-cost, low-impact urban seismic surveys are possible with DAS, which uses dynamic strain sensing to record seismic waves incident to a buried fiber optic cable. However, interferometry and tomography of ambient noise data recorded in urban areas include coherent noise from near-field infrastructure such as cars and trains passing the array, in some cases causing artifacts in estimated Green's functions and potentially incorrect surface wave velocities. Based on our comparison of several methods, we propose an automated, real-time data processing workflow to detect and reduce the impact of these events on data from a dense array in an urban environment. We utilize a recursive STA/LTA (short-term average/long-term average) algorithm on each channel to identify sharp amplitude changes typically associated with an event arrival. In order to distinguish between optical noise and physical events, an event is cataloged only if STA/LTA is triggered on enough channels across the array in a short time window. For each event in the catalog, a conventional semblance analysis is performed across a straight segment of the array to determine whether the event has a coherent velocity signature. Events that demonstrate a semblance peak at low apparent velocities (5-50 m/s) are assumed to represent coherent transportation-related noise and are down-weighted in the time domain before cross-correlation. We show the impact of removing such noise on estimated Green's functions from ambient noise data recorded in Richmond, CA in December 2014. This method has been developed for use on a continuous time-lapse ambient noise survey collected with DAS near Fairbanks, AK, and an upcoming ambient noise survey on the Stanford University campus using DAS with a re

  7. Nocturnal aircraft noise effects.

    PubMed

    Basner, M; Samel, A

    2004-01-01

    Noise protection associated with the construction and extension of airports in the Federal Republic of Germany has been regulated by the law for protection against aircraft noise since 1971. This legislation is due for revision because of different aspects. One aspect is the growth of air traffic which has led many airports to the limits of their capacity and in search of new ways of adaptation to the increasing demand for flight services. Another aspect is the increasing concern of the population about noise effects which has to be addressed by better protection against the effects of aircraft noise. The framework conditions of policy in terms of society as a whole, its health and economic environment need to be put into effect by political action. Science can contribute to this goal by performing noise effects research and by providing recommendations to the political body. However, it remains controversial, what measures are necessary or adequate to assure effective protection of the population against aircraft noise. This is particularly true for the protection of rest and sleep at night. The problem of finding a common basis for adequate recommendations is associated with (1) the low number of primary studies, which also exhibited highly variable results and assessments, (2) the handling of acoustic or psycho-acoustic dimensions for quantifying psychological or physiological reactions, and (3) the conception of how far preventive measures have to go to prove effective. With this in mind, the DLR Institute for Aerospace Medicine is conducting a large-scale, multi-stage study for investigating the acute effects of nocturnal aircraft noise on human sleep. This enterprise is implemented in the framework of the HGF/DLR project "Quiet Air Traffic" for developing sustainable assessment criteria for human-specific effects of aircraft noise at night.

  8. Empirical prediction of peak pressure levels in anthropogenic impulsive noise. Part I: Airgun arrays signals.

    PubMed

    Galindo-Romero, Marta; Lippert, Tristan; Gavrilov, Alexander

    2015-12-01

    This paper presents an empirical linear equation to predict peak pressure level of anthropogenic impulsive signals based on its correlation with the sound exposure level. The regression coefficients are shown to be weakly dependent on the environmental characteristics but governed by the source type and parameters. The equation can be applied to values of the sound exposure level predicted with a numerical model, which provides a significant improvement in the prediction of the peak pressure level. Part I presents the analysis for airgun arrays signals, and Part II considers the application of the empirical equation to offshore impact piling noise.

  9. Characterization of the Acoustic Field in Marine Environments with Anthropogenic Noise

    NASA Astrophysics Data System (ADS)

    Guan, Shane

    Most animals inhabit the aquatic environment are acoustical-oriented, due to the physical characteristics of water that favors sound transmission. Many aquatic animals depend on underwater sound to navigate, communicate, find prey, and avoid predators. The degradation of underwater acoustic environment due to human activities is expected to affected these animals' well-being and survival at the population level. This dissertation presents three original studies on the characteristics and behavior of underwater sound fields in three unique marine environments with anthropogenic noises. The first study examines the soundscape of the Chinese white dolphin habitat in Taiwan. Acoustic recordings were made at two coastal shallow water locations, Yunlin and Waisanding, in 2012. Results show that croaker choruses are dominant sound sources in the 1.2--2.4 kHz frequency band for both locations at night, and noises from container ships in the 150--300 Hz frequency band define the relative higher broadband sound levels at Yunlin. Results also illustrate interrelationships among different biotic, abiotic, and anthropogenic elements that shape the fine-scale soundscape in a coastal environment. The second study investigates the inter-pulse sound field during an open-water seismic survey in coastal shallow waters of the Arctic. The research uses continuous acoustic recordings collected from one bottom-mounted hydrophone deployed in the Beaufort Sea in summer 2012. Two quantitative methods were developed to examine the inter-pulse sound field characteristics and its dependence on source distances. Results show that inter-pulse sound field could raise the ambient noise floor by as much as 9 dB, depending on ambient condition and source distance. The third study examines the inter-ping sound field of simulated mid-frequency active sonar in deep waters off southern California in 2013 and 2014. The study used drifting acoustic recorder buoys to collect acoustic data during sonar

  10. Documenting and Assessing Dolphin Calls and Ambient and Anthropogenic Noise Levels via PAM and a SPL Meter.

    PubMed

    Dudzinski, Kathleen M; Melillo-Sweeting, Kelly; Gregg, Justin D

    2016-01-01

    Song Meter SM2M marine recorders were deployed to document dolphin calls and ambient and anthropogenic noise. Recordings from Bimini were split into 2-h segments; no segment was without dolphin calls. At Dolphin Encounters, average noise levels ranged from 110 to 125 dB; the highest source level was 147.98 dB re 1 μPa at 1 m. Average ambient-noise levels documented at 4 sites in Guam were below 118 dB re 1 μPa at 1 m. These data were compared with values from a custom-built sound pressure level (SPL) meter and confirm that the SM2M recorder is a useful tool for assessing animal calls and ambient and anthropogenic noise levels.

  11. Climatic and anthropogenic stress on water levels: basin-scale observations with seismic noise

    NASA Astrophysics Data System (ADS)

    Lecocq, Thomas; Pedersen, Helle; Brenguier, Florent; Stammler, Klaus

    2016-04-01

    Monitoring changes in shear wave velocities within the crust have become possible through recently developed techniques based on seismic noise analysis. In the present work we address the challenge of using these techniques for environmental monitoring at upper crustal level. Our work is based on data from the broadband Gräfenberg array (Germany) which was installed in 1976 and for which the continuous data acquired has been preserved until today. Using state of the art pre-processing and cross-correlation techniques (MSNoise), we computed daily cross-correlation functions (CCF) between 4 stations (6 pairs) of the Gräfenberg array over the period 1977-2007. The daily CCFs are then stacked to form an average CCF per month. Instead of doing classic "one versus reference" comparisons, the monthly CCFs are compared pairwise using Moving Window Cross-Spectral analysis (MWCS). In total, 387 720 MWCS have been computed between 20 s and 80 s lapse time to obtain relative velocity changes (dv/v). All dv/v are then inverted using a Bayesian weighted least square procedure. Depending on the smoothing weight used during the inversion, seasonal to long term trends can be evidenced. The results show clear and stable trends in the data. We present possible causes explaining these trends and abrupt changes of dv/v by showing modelled (GLDAS) and observed climatic data together with anthropogenic observables. A combination of climatic (warmer surface temperatures, less rainfall) and anthropogenic (more population, more irrigated land) factors are the most probable causes of the progressive relative increase of seismic velocities under the Gräfenberg array. We interpret these results as a progressive depletion of the water resources in the large karstified Malm reservoir (Late Jurassic) below the array.

  12. First indications that northern bottlenose whales are sensitive to behavioural disturbance from anthropogenic noise

    PubMed Central

    Miller, P. J. O.; Kvadsheim, P. H.; Lam, F. P. A.; Tyack, P. L.; Curé, C.; DeRuiter, S. L.; Kleivane, L.; Sivle, L. D.; van IJsselmuide, S. P.; Visser, F.; Wensveen, P. J.; von Benda-Beckmann, A. M.; Martín López, L. M.; Narazaki, T.; Hooker, S. K.

    2015-01-01

    Although northern bottlenose whales were the most heavily hunted beaked whale, we have little information about this species in its remote habitat of the North Atlantic Ocean. Underwater anthropogenic noise and disruption of their natural habitat may be major threats, given the sensitivity of other beaked whales to such noise disturbance. We attached dataloggers to 13 northern bottlenose whales and compared their natural sounds and movements to those of one individual exposed to escalating levels of 1–2 kHz upsweep naval sonar signals. At a received sound pressure level (SPL) of 98 dB re 1 μPa, the whale turned to approach the sound source, but at a received SPL of 107 dB re 1 μPa, the whale began moving in an unusually straight course and then made a near 180° turn away from the source, and performed the longest and deepest dive (94 min, 2339 m) recorded for this species. Animal movement parameters differed significantly from baseline for more than 7 h until the tag fell off 33–36 km away. No clicks were emitted during the response period, indicating cessation of normal echolocation-based foraging. A sharp decline in both acoustic and visual detections of conspecifics after exposure suggests other whales in the area responded similarly. Though more data are needed, our results indicate high sensitivity of this species to acoustic disturbance, with consequent risk from marine industrialization and naval activity. PMID:26543576

  13. First indications that northern bottlenose whales are sensitive to behavioural disturbance from anthropogenic noise.

    PubMed

    Miller, P J O; Kvadsheim, P H; Lam, F P A; Tyack, P L; Curé, C; DeRuiter, S L; Kleivane, L; Sivle, L D; van IJsselmuide, S P; Visser, F; Wensveen, P J; von Benda-Beckmann, A M; Martín López, L M; Narazaki, T; Hooker, S K

    2015-06-01

    Although northern bottlenose whales were the most heavily hunted beaked whale, we have little information about this species in its remote habitat of the North Atlantic Ocean. Underwater anthropogenic noise and disruption of their natural habitat may be major threats, given the sensitivity of other beaked whales to such noise disturbance. We attached dataloggers to 13 northern bottlenose whales and compared their natural sounds and movements to those of one individual exposed to escalating levels of 1-2 kHz upsweep naval sonar signals. At a received sound pressure level (SPL) of 98 dB re 1 μPa, the whale turned to approach the sound source, but at a received SPL of 107 dB re 1 μPa, the whale began moving in an unusually straight course and then made a near 180° turn away from the source, and performed the longest and deepest dive (94 min, 2339 m) recorded for this species. Animal movement parameters differed significantly from baseline for more than 7 h until the tag fell off 33-36 km away. No clicks were emitted during the response period, indicating cessation of normal echolocation-based foraging. A sharp decline in both acoustic and visual detections of conspecifics after exposure suggests other whales in the area responded similarly. Though more data are needed, our results indicate high sensitivity of this species to acoustic disturbance, with consequent risk from marine industrialization and naval activity.

  14. [Cardiovascular effects of noise].

    PubMed

    Vacheron, A

    1992-03-01

    The circulatory response to noise is dominated by a peripheral blood vessels vasoconstriction, of greater magnitude when asleep than awake. Noise of lower frequency seems more able to produce this response. With repetition of the noise, adaptation and tolerance to it quickly appears. Meanwhile prolonged high level noise exposition induces an increasing prevalence of arterial hypertension among industrial workers. This increase is also clearly found in residential communities living near airports. Long-term exposure to noise is a dangerous nuisance, that can lead to an increase in arterial blood pressure and favour coronary artery disease development.

  15. Anthropogenic noise, but not artificial light levels predicts song behaviour in an equatorial bird.

    PubMed

    Dorado-Correa, Adriana M; Rodríguez-Rocha, Manuel; Brumm, Henrik

    2016-07-01

    Birds in cities start singing earlier in the morning than in rural areas; commonly this shift is attributed to light pollution. Some studies have suggested that traffic noise has a stronger influence on singing activity than artificial light does. Changes in the timing of singing behaviour in relation to noise and light pollution have only been investigated in the temperate zones. Tropical birds, however, experience little seasonal variation in day length and may be less dependent on light intensity as a modifier for reproductive behaviours such as song. To test whether noise or light pollution has a stronger impact on the dawn chorus of a tropical bird, we investigated the singing behaviour of rufous-collared sparrows (Zonotrichia capensis) in Bogota, Colombia at two times during the year. We found that birds in places with high noise levels started to sing earlier. Light pollution did not have a significant effect. Birds may begin to sing earlier in noisy areas to avoid acoustic masking by traffic later in the morning. Our results also suggest that some tropical birds may be less sensitive to variations in day length and thus less sensitive to light pollution.

  16. Anthropogenic noise, but not artificial light levels predicts song behaviour in an equatorial bird

    PubMed Central

    Rodríguez-Rocha, Manuel; Brumm, Henrik

    2016-01-01

    Birds in cities start singing earlier in the morning than in rural areas; commonly this shift is attributed to light pollution. Some studies have suggested that traffic noise has a stronger influence on singing activity than artificial light does. Changes in the timing of singing behaviour in relation to noise and light pollution have only been investigated in the temperate zones. Tropical birds, however, experience little seasonal variation in day length and may be less dependent on light intensity as a modifier for reproductive behaviours such as song. To test whether noise or light pollution has a stronger impact on the dawn chorus of a tropical bird, we investigated the singing behaviour of rufous-collared sparrows (Zonotrichia capensis) in Bogota, Colombia at two times during the year. We found that birds in places with high noise levels started to sing earlier. Light pollution did not have a significant effect. Birds may begin to sing earlier in noisy areas to avoid acoustic masking by traffic later in the morning. Our results also suggest that some tropical birds may be less sensitive to variations in day length and thus less sensitive to light pollution. PMID:27493778

  17. Effects of background noise on total noise annoyance

    NASA Technical Reports Server (NTRS)

    Willshire, K. F.

    1987-01-01

    Two experiments were conducted to assess the effects of combined community noise sources on annoyance. The first experiment baseline relationships between annoyance and noise level for three community noise sources (jet aircraft flyovers, traffic and air conditioners) presented individually. Forty eight subjects evaluated the annoyance of each noise source presented at four different noise levels. Results indicated the slope of the linear relationship between annoyance and noise level for the traffic noise was significantly different from that of aircraft and of air conditioner noise, which had equal slopes. The second experiment investigated annoyance response to combined noise sources, with aircraft noise defined as the major noise source and traffic and air conditioner noise as background noise sources. Effects on annoyance of noise level differences between aircraft and background noise for three total noise levels and for both background noise sources were determined. A total of 216 subjects were required to make either total or source specific annoyance judgements, or a combination of the two, for a wide range of combined noise conditions.

  18. Neither artificial light at night, anthropogenic noise nor distance from roads are associated with oxidative status of nestlings in an urban population of songbirds.

    PubMed

    Casasole, Giulia; Raap, Thomas; Costantini, David; AbdElgawad, Hamada; Asard, Han; Pinxten, Rianne; Eens, Marcel

    2017-08-01

    Increasing urbanization is responsible for road-related pollutants and causes an unprecedented increase in light and noise pollution, with potential detrimental effects for individual animals, communities and ecosystems. These stressors rarely act in isolation but studies dissecting the effects of these multiple stressors are lacking. Moreover, studies on urban stressors have mainly focused on adults, while exposure in early-life may be detrimental but is largely ignored. To fill this important knowledge gap, we studied if artificial light at night, anthropogenic noise and road-related pollution (using distance from roads as a proxy) explain variation in oxidative status in great tit nestlings (Parus major) in an urban population. Artificial light at night, anthropogenic noise and distance from roads were not associated with variation of the nine studied metrics of oxidative status (superoxide dismutase-SOD-, glutathione peroxidase-GPX, catalase-CAT-, non-enzymatic total antioxidant capacity-TAC-, reduced glutathione-GSH-, oxidized glutathione-GSSG-, ratio GSH/GSSG, protein carbonyls and thiobarbituric acid reactive substances-TBARS). Interestingly, for all oxidative status metrics, we found that there was more variation in oxidative status among individuals of the same nest compared to between different nests. We also showed an increase in protein carbonyls and a decrease of the ratio GSH/GSSG as the day advanced, and an increase of GPX when weather conditions deteriorated. Our study suggests that anthropogenic noise, artificial light at night and road-related pollution are not the most important sources of variation in oxidative status in great tit nestlings. It also highlights the importance of considering bleeding time and weather conditions in studies with free-living animals. Copyright © 2017. Published by Elsevier Inc.

  19. Resilience of southwestern Amazon forests to anthropogenic edge effects.

    PubMed

    Phillips, Oliver L; Rose, Sam; Mendoza, Abel Monteagudo; Vargas, Percy Núñez

    2006-12-01

    Anthropogenic edge effects can compromise the conservation value of mature tropical forests. To date most edge-effect research in Amazonia has concentrated on forests in relatively seasonal locations or with poor soils in the east of the basin. We present the first evaluation from the relatively richer soils of far western Amazonia on the extent to which mature forest biomass, diversity, and composition are affected by edges. In a southwestern Amazonian landscape we surveyed woody plant diversity, species composition, and biomass in 88x0.1 ha samples of unflooded forest that spanned a wide range in soil properties and included samples as close as 50 m and as distant as >10 km from anthropogenic edges. We applied Mantel tests, multiple regression on distance matrices, and other multivariate techniques to identify anthropogenic effects before and after accounting for soil factors and spatial autocorrelation. The distance to the nearest edge, access point, and the geographical center of the nearest community ("anthropogenic-distance effects") all had no detectable effect on tree biomass or species diversity. Anthropogenic-distance effects on tree species composition were also below the limits of detection and were negligible in comparison with natural environmental and spatial factors. Analysis of the data set's capacity to detect anthropogenic effects confirmed that the forests were not severely affected by edges, although because our study had few plots within 100 m of forest edges, our confidence in patterns in the immediate vicinity of edges is limited. It therefore appears that the conservation value of most "edge" forests in this region has not yet been compromised substantially. We caution that because this is one case study it should not be overinterpreted, but one explanation for our findings may be that western Amazonian tree species are naturally faster growing and more disturbance adapted than those farther east.

  20. Physiological, Psychological, and Social Effects of Noise

    NASA Technical Reports Server (NTRS)

    Kryter, K. D.

    1984-01-01

    The physiological, and behavioral effects of noise on man are investigated. Basic parameters such as definitions of noise, measuring techniques of noise, and the physiology of the ear are presented prior to the development of topics on hearing loss, speech communication in noise, social effects of noise, and the health effects of noise pollution. Recommendations for the assessment and subsequent control of noise is included.

  1. Aviation Noise Effects,

    DTIC Science & Technology

    1985-03-01

    included , ,.,-,;. 17 e18 . Distribution StatementA rcrafe, aviation, noise, annoyance, This document is available to the public helicopter, sleep, speech...measurement of real-ear protection of hearing protectors and physical attenuation of earmuffs. ANSI/ ASTM E336-77 (1977): Standard test method for...measurement of airborne sound insulation in buildings. ANSI/ ASTM E413-73 (1980): Standard classification for sound transmission class. ANSI/SAE ARP1071

  2. Anthropogenic effects on subsurface temperature in Bangkok

    NASA Astrophysics Data System (ADS)

    Taniguchi, M.

    2006-09-01

    Subsurface temperatures in Bangkok, where population and density increase rapidly, were analyzed to evaluate the effects of surface warming due to urbanization. The magnitude of surface warming evaluated from subsurface temperature in Bangkok was 1.7°C which agreed with meteorological data during the last 50 years. The depth apart from steady thermal gradient, which shows an indicator of the magnitude of surface warming due to additional heat from urbanization, was deeper at the center of the city than in the suburb areas of Bangkok. In order to separate surface warming effects into global warming effect and urbanization effect, analyses of subsurface temperature have been done depending on the distance from the city center. The results show that the expansion of urbanization in Bangkok reaches up to 80 km from the city center.

  3. Quantitative Measures of Anthropogenic Noise on Harbor Porpoises: Testing the Reliability of Acoustic Tag Recordings.

    PubMed

    Wisniewska, Danuta M; Teilmann, Jonas; Hermannsen, Line; Johnson, Mark; Miller, Lee A; Siebert, Ursula; Madsen, Peter Teglberg

    2016-01-01

    In recent years, several sound and movement recording tags have been developed to sample the acoustic field experienced by cetaceans and their reactions to it. However, little is known about how tag placement and an animal's orientation in the sound field affect the reliability of on-animal recordings as proxies for actual exposure. Here, we quantify sound exposure levels recorded with a DTAG-3 tag on a captive harbor porpoise exposed to vessel noise in a controlled acoustic environment. Results show that flow noise is limiting onboard noise recordings, whereas no evidence of body shading has been found for frequencies of 2-20 kHz.

  4. The Effects of Noise on Pupil Performance.

    ERIC Educational Resources Information Center

    Slater, Barbara Ruth

    Effects of school noise conditions on student written task performance were studied. Three noise levels were examined--(1) irregular interval noise, 75-90 decibels, (2) average or normal noise, and (3) quiet condition, 45-55 decibels. An attempt was made to reproduce noise conditions typical of the school environment. A second controlled…

  5. Effects of noise upon human information processing

    NASA Technical Reports Server (NTRS)

    Cohen, H. H.; Conrad, D. W.; Obrien, J. F.; Pearson, R. G.

    1974-01-01

    Studies of noise effects upon human information processing are described which investigated whether or not effects of noise upon performance are dependent upon specific characteristics of noise stimulation and their interaction with task conditions. The difficulty of predicting noise effects was emphasized. Arousal theory was considered to have explanatory value in interpreting the findings of all the studies. Performance under noise was found to involve a psychophysiological cost, measured by vasoconstriction response, with the degree of response cost being related to scores on a noise annoyance sensitivity scale. Noise sensitive subjects showed a greater autonomic response under noise stimulation.

  6. Improved representation of stratocumulus clouds and the anthropogenic aerosol effect

    NASA Astrophysics Data System (ADS)

    Neubauer, David; Lohmann, Ulrike; Hoose, Corinna; Frontoso, Grazia M.

    2014-05-01

    Stratocumulus clouds are important for future climate predictions as they have a strong cooling effect and the feedback of low clouds is believed to be a major cause of the model spread in climate sensitivity. Stratocumulus clouds are difficult to represent in a general circulation model because of their small vertical extent. Stratocumulus regions are also areas of a strong anthropogenic aerosol effect. Simulations of the anthropogenic aerosol effect can be expected to depend on the representation of stratocumulus clouds in climate models. We address the representation of several of the physical processes that have to be accounted for when modeling stratocumuli in the general circulation model ECHAM6 (Stevens et al., 2013) coupled to the aerosol module HAM2 (Zhang et al., 2012). As a 'long tail' stability function can lead to excessive mixing at high stabilities we replaced it with a 'sharp' stability function. The stratocumulus cloud cover and liquid water path increase, similar to previous studies, with the 'sharp' stability function in ECHAM6-HAM2. We also study the impact of increased vertical resolution in the lower troposphere in ECHAM6-HAM2 on stratocumulus clouds. First results show improvements for the cloud height and thickness with increased vertical resolution. To simulate a realistic mixing state and size of particles released by evaporation of clouds and precipitation we include aerosol processing in stratiform clouds. First results from multi-year simulations show that using a 'sharp' stability function decreases the anthropogenic aerosol effect from -1.5 W/m2 to -1.2 W/m2 and in-cloud aerosol processing to -0.8 W/m2. This strong decrease is due to an increase in the background aerosol load. Increased vertical resolution doesn't seem to affect the anthropogenic aerosol effect in the global average. Further results on the impact of changing the vertical resolution, a different stability function and in-cloud aerosol processing in ECHAM6-HAM2 on the

  7. Auditory Masking Patterns in Bottlenose Dolphins from Anthropogenic and Natural Noise Sources

    DTIC Science & Technology

    2013-09-30

    e.g., critical ratios ) are often used to describe and predict auditory masking. For this task, detection thresholds for a 10 kHz tone were measured in...unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 2 determine the relationship between noise metrics and masked tonal ...the residual errors (FIG 3) demonstrates that the two-parameter model produces much better fits than critical ratio predictions, while still being

  8. Health Effects of Noise Exposure in Children.

    PubMed

    Stansfeld, Stephen; Clark, Charlotte

    2015-06-01

    Environmental noise exposure, such as road traffic noise and aircraft noise, is associated with a range of health outcomes in children. Children demonstrate annoyance responses to noise, and noise is also related to lower well-being and stress responses, such as increased levels of adrenaline and noradrenaline. Noise does not cause more serious mental health problems, but there is growing evidence for an association with increased hyperactivity symptoms. Studies also suggest that noise might cause changes in cardiovascular functioning, and there is some limited evidence for an effect on low birth weight. There is robust evidence for an effect of school noise exposure on children's cognitive skills such as reading and memory, as well as on standardised academic test scores. Environmental noise does not usually reach levels that are likely to affect children's hearing; however, increasing use of personal electronic devices may leave some children exposed to harmful levels of noise.

  9. A radiohydroacoustic station for monitoring the parameters of anthropogenic impulse and noise signals on the shelf

    NASA Astrophysics Data System (ADS)

    Rutenko, A. N.; Borisov, S. V.; Kovzel', D. G.; Gritsenko, V. A.

    2015-07-01

    The paper presents a description and the technical characteristics of an autonomous hydroacoustic station developed at the Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences (TOI DVO RAN) for stationary measurements of variations in acoustic pressure in the frequency range of 2-15 000 Hz on the shelf at the bottom. To organize real-time monitoring of the parameters of seismic survey impulse signals and industrial acoustic noise, the station is additionally equipped with a digital UHF-FM radio telemetry channel. Acoustic data measured in the frequency band of 2-2000 Hz is transmitted through the channel to a shore post, as well as via an Iridium satellite radio telemetry channel. It controls the operation of the UHF-FM radio transmitter and transmits the results of special analysis of acoustic data obtained in subsequent 1 min time intervals.

  10. Global scale precipitation from monthly to centennial scales: empirical space-time scaling analysis, anthropogenic effects

    NASA Astrophysics Data System (ADS)

    de Lima, Isabel; Lovejoy, Shaun

    2016-04-01

    The characterization of precipitation scaling regimes represents a key contribution to the improved understanding of space-time precipitation variability, which is the focus here. We conduct space-time scaling analyses of spectra and Haar fluctuations in precipitation, using three global scale precipitation products (one instrument based, one reanalysis based, one satellite and gauge based), from monthly to centennial scales and planetary down to several hundred kilometers in spatial scale. Results show the presence - similarly to other atmospheric fields - of an intermediate "macroweather" regime between the familiar weather and climate regimes: we characterize systematically the macroweather precipitation temporal and spatial, and joint space-time statistics and variability, and the outer scale limit of temporal scaling. These regimes qualitatively and quantitatively alternate in the way fluctuations vary with scale. In the macroweather regime, the fluctuations diminish with time scale (this is important for seasonal, annual, and decadal forecasts) while anthropogenic effects increase with time scale. Our approach determines the time scale at which the anthropogenic signal can be detected above the natural variability noise: the critical scale is about 20 - 40 yrs (depending on the product, on the spatial scale). This explains for example why studies that use data covering only a few decades do not easily give evidence of anthropogenic changes in precipitation, as a consequence of warming: the period is too short. Overall, while showing that precipitation can be modeled with space-time scaling processes, our results clarify the different precipitation scaling regimes and further allow us to quantify the agreement (and lack of agreement) of the precipitation products as a function of space and time scales. Moreover, this work contributes to clarify a basic problem in hydro-climatology, which is to measure precipitation trends at decadal and longer scales and to

  11. Rarity Value and Species Extinction: The Anthropogenic Allee Effect

    PubMed Central

    Courchamp, Franck; Signoret, Laetitia; Bull, Leigh; Meinard, Yves

    2006-01-01

    Standard economic theory predicts that exploitation alone is unlikely to result in species extinction because of the escalating costs of finding the last individuals of a declining species. We argue that the human predisposition to place exaggerated value on rarity fuels disproportionate exploitation of rare species, rendering them even rarer and thus more desirable, ultimately leading them into an extinction vortex. Here we present a simple mathematical model and various empirical examples to show how the value attributed to rarity in some human activities could precipitate the extinction of rare species—a concept that we term the anthropogenic Allee effect. The alarming finding that human perception of rarity can precipitate species extinction has serious implications for the conservation of species that are rare or that may become so, be they charismatic and emblematic or simply likely to become fashionable for certain activities. PMID:17132047

  12. Migrating Mule Deer: Effects of Anthropogenically Altered Landscapes

    PubMed Central

    Lendrum, Patrick E.; Anderson, Charles R.; Monteith, Kevin L.; Jenks, Jonathan A.; Bowyer, R. Terry

    2013-01-01

    Background Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue. Methodology/Principal Findings We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus) in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008–2010. Conclusions/Significance Timing of spring migration was related to winter weather (particularly snow depth) and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have

  13. Scaling of The Tropospheric Ozone Concentrations and Anthropogenic Effects

    NASA Astrophysics Data System (ADS)

    Audiffren, N.; Duroure, C.

    The statistical characteristics of long time series of ozone mixing ratios in free tro- posphere and in urban environment are compared.We use a five year dataset with 15 minute resolution of ozone concentrations in a free tropospheric condition (Puy de Dôme) and in four different towns in the mesoscale vicinity (Auvergne region), (data from Atmo-Auvergne) The free tropospheric ozone field have the same scaling behaviour (Fourier spectrum, structure functions and intermittency measure) than a passive scalar in a 3D higthly turbulent dynamic field. We don't observe a mesoscale gap and the inertial range is ranging from (at least) one minute to a few days for eule- rian measurements (from hundred meters to hundreds of kilometers for the lagrangian space scale). The probability density functions (PDF) of the ozone mixing ratio incre- ments are higthly non gaussian, with tails decreasing slower than negative exponential, indicating an "intermittent" behaviour. The scale evolution of the intermittency is esti- mated using the normalized fourth moment of the discrete laplacian and is compared with other turbulent geophysical fields (mesoscale cloud coverage, updraft velocity, rainfall serie). On the opposite, for the urban measurements, the modifications of the statistical properties not only affect the mean but also the scaling exponent (Fourier slope closer to -1) and the intermittency structure function. The one day periodic peak is more pronounced than for the free troposphere measurements and appears a (purely anthropogenic) peak of seven days. For large towns ,the PDF of gradient are close to a Levy-stable PDF with a characteristic exponent close to 2 (the Gaussian limit). The anthropogenic effects on ozone concentration make the statistical characteristics closer to those observed for the web flux, the traffic jams, or the properties of speach and music.

  14. Migrating mule deer: effects of anthropogenically altered landscapes.

    PubMed

    Lendrum, Patrick E; Anderson, Charles R; Monteith, Kevin L; Jenks, Jonathan A; Bowyer, R Terry

    2013-01-01

    Migration is an adaptive strategy that enables animals to enhance resource availability and reduce risk of predation at a broad geographic scale. Ungulate migrations generally occur along traditional routes, many of which have been disrupted by anthropogenic disturbances. Spring migration in ungulates is of particular importance for conservation planning, because it is closely coupled with timing of parturition. The degree to which oil and gas development affects migratory patterns, and whether ungulate migration is sufficiently plastic to compensate for such changes, warrants additional study to better understand this critical conservation issue. We studied timing and synchrony of departure from winter range and arrival to summer range of female mule deer (Odocoileus hemionus) in northwestern Colorado, USA, which has one of the largest natural-gas reserves currently under development in North America. We hypothesized that in addition to local weather, plant phenology, and individual life-history characteristics, patterns of spring migration would be modified by disturbances associated with natural-gas extraction. We captured 205 adult female mule deer, equipped them with GPS collars, and observed patterns of spring migration during 2008-2010. Timing of spring migration was related to winter weather (particularly snow depth) and access to emerging vegetation, which varied among years, but was highly synchronous across study areas within years. Additionally, timing of migration was influenced by the collective effects of anthropogenic disturbance, rate of travel, distance traveled, and body condition of adult females. Rates of travel were more rapid over shorter migration distances in areas of high natural-gas development resulting in the delayed departure, but early arrival for females migrating in areas with high development compared with less-developed areas. Such shifts in behavior could have consequences for timing of arrival on birthing areas, especially where

  15. Effects of environmental noise on sleep.

    PubMed

    Hume, Kenneth I; Brink, Mark; Basner, Mathias

    2012-01-01

    This paper summarizes the findings from the past 3 year's research on the effects of environmental noise on sleep and identifies key future research goals. The past 3 years have seen continued interest in both short term effects of noise on sleep (arousals, awakenings), as well as epidemiological studies focusing on long term health impacts of nocturnal noise exposure. This research corroborated findings that noise events induce arousals at relatively low exposure levels, and independent of the noise source (air, road, and rail traffic, neighbors, church bells) and the environment (home, laboratory, hospital). New epidemiological studies support already existing evidence that night-time noise is likely associated with cardiovascular disease and stroke in the elderly. These studies collectively also suggest that nocturnal noise exposure may be more relevant for the genesis of cardiovascular disease than daytime noise exposure. Relative to noise policy, new effect-oriented noise protection concepts, and rating methods based on limiting awakening reactions were introduced. The publications of WHO's ''Night Noise Guidelines for Europe'' and ''Burden of Disease from Environmental Noise'' both stress the importance of nocturnal noise exposure for health and well-being. However, studies demonstrating a causal pathway that directly link noise (at ecological levels) and disturbed sleep with cardiovascular disease and/or other long term health outcomes are still missing. These studies, as well as the quantification of the impact of emerging noise sources (e.g., high speed rail, wind turbines) have been identified as the most relevant issues that should be addressed in the field on the effects of noise on sleep in the near future.

  16. Effects of traffic noise on the calling behavior of two Neotropical hylid frogs

    PubMed Central

    Cechin, Sonia; Antunes, Rógger; Borges-Martins, Márcio

    2017-01-01

    Anthropogenic disturbance has been pointed to as one of the major causes of the world´s biodiversity crisis. Among them, noise pollution is a potential underestimated threat, projected to increase in the next decades accompanying urban expansion. Rising levels of noise pollution may result in negative impacts on species highly dependent on acoustic communication. Amphibians have long served as model organisms for investigating animal acoustic communication because their reproduction depends on transmitting and receiving acoustic signals. A few studies have investigated the effects of anthropogenic noise on anurans, but there is still limited knowledge on how it affects them. In this study, we test the effect of two intensities of traffic noise on calling males of two Neotropical treefrogs species. We expect to record more changes in call parameters, to avoid masking effect, at higher intensity noise treatments, and in the species with higher call/noise frequency overlap. We performed a set of field playback experiments exposing male frogs to road noise at two different intensities (65dB and 75dB). Focal species are Boana bischoffi (high call/noise frequency overlap) and B. leptolineata (low call/noise frequency overlap). Both species changed acoustic parameters during or after the exposure to traffic noise. Advertisement call rate of B. bischoffi decreased during road noise, and dominant frequency decreased over time. Call length of B. leptolineata increased or decreased, depending on the order of noise intensity. We also observed spatial displacement in both species, which moved away from the noise source. Our results provide evidence that traffic noise affects anuran calling behavior, and noise intensity is an important factor affecting how species respond. PMID:28854253

  17. Effect of helicopter noise on passenger annoyance

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Leatherwood, J. D.

    1979-01-01

    The effects of helicopter interior noise on passenger annoyance for both reverie and listening situations was investigated. The relative effectiveness of several metrics for quantifying annoyance response for these situations was also studied. The noise stimuli were based upon recordings of the interior noise of civil helicopter research aircraft. These noises were presented at levels ranging from approximately 70 to 86 d with various tonal components selectively attenuated to give a range of spectra. The listening task required the subjects to listen to and record phonetically-balanced words presented within the various noise environments. Results indicate that annoyance during a listening condition is generally higher than annoyance under a reverie condition for corresponding interior noise environments. Attenuation of the tonal components results in increases in listening performance but has only a small effect upon annoyance for a given noise level.

  18. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    USGS Publications Warehouse

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

  19. An overview of health effects on noise

    NASA Astrophysics Data System (ADS)

    Osada, Y.

    1988-12-01

    Although noise can damage the inner ear and cause other pathological changes, its most common negative effects are non-somatic, such as a perception of noisiness and disturbance of daily activities. According to the definition of health by WHO, this should be considered as a health hazard. These health effects of noise can be classified into the following three categories: (I) hearing loss, perception of noisiness and masking are produced along the auditory pathway and are thus direct and specific effects of noise; (II) interference with performance, rest and sleep, a feeling of discomfort and some physiological effects are produced as indirect and non-specific effects via reticular formation of the midbrain; (III) annoyance is not merely a feeling of unpleasantness but the feeling of being bothered or troubled, and includes the development of a particular attitude toward the noise source. Individual or group behavioral responses will be evoked when annoyance develops. Annoyance and behavioral response are integrated and composite effects. The health effects of noise are modified by many factors related to both the noise and the individual. Noise level, frequency spectrum, duration and impulsiveness modify the effects. Sex, age, health status and mental character also have an influence on the effects. Direct effects of noise are most dependent on the physical nature of the noise and least dependent on human factors. Indirect effects are more dependent, and integrated effects most dependent, on human factors.

  20. Apparent Detection of Global Anthropogenic Effects Extending Into the Thermosphere

    NASA Astrophysics Data System (ADS)

    Keating, G. M.; Theriot, M. E.; Akmaev, R. A.; Bougher, S. W.

    2004-05-01

    From a study of long-term orbital decay of Earth satellites, it has been discovered that thermospheric densities have declined substantially since at least 1976. Detection of this decline was first published by Keating et al (2000) in Geophysical Research Letters. They performed an analysis of 5 Earth satellites with periapsis altitudes near 380 km. The study was conducted for conditions near solar minimum to remove the effect of the 11-year solar cycle. Comparisons were made with a standard empirical density model to remove the effects of variations in solar and geomagnetic activity, altitude, season, latitude, time of day, etc. In that article, it was proposed that the cooling trend was caused by anthropogenic effects. Now the data set has been expanded to 14 satellites near 380 km to obtain an improved estimate of the trend and to establish possible variations in the trend. In the new study, the average trend from 1976-1996 is found to be minus 10.3 plus or minus 1.2 percent. This is in accord with the 2000 paper, which gave an average trend of minus 9.8 plus or minus 2.5 percent. The new results show statistically insignificant differences between the trend at low and high latitudes indicating a global response with no significant correlation to geomagnetic activity variations. The results appear to be in accord with theoretical model estimates for the response of the thermosphere to increases in CO2 and CH4 predicted by Roble and Dickinson (1989), Rishbeth and Roble (1992), and Akmaev and Formichev (2000). A paper by Emmert et al (2004) using a similar approach of studying the orbital decay from 27 satellites qualitatively confirms the downward trend originally discovered in the 2000 paper. All 27 of the satellites they studied indicated a downward trend. Twenty of the 27 satellites experienced a decrease in thermospheric density at somewhat higher altitudes, between 500 and 700 km. It is estimated that CO2 will double before the end of this century

  1. Effects of aircraft noise on human activities

    NASA Technical Reports Server (NTRS)

    Arnoult, M. D.; Gilfillan, L. G.

    1983-01-01

    The effects of aircrft noise on human activities was investigated by developing a battery of tasks (1) representative of a range of human activities and (2) sensitive to the disruptive effects of noise. The noise used were recordings of jet aircraft and helicopter sounds at three lvels of loudness--60, 70, and 80 dB(A). Experiment 1 investigated 12 different cognitive tasks, along with two intelligibility tasks included to validate that the noises were being effective. Interference with intelligibility was essentially the same as found in the research literature, but only inconsistent effects were found on either accuracy or latency of performance on the cognitive tasks. When the tasks were grouped into four categories (Intelligibility, Matching, Verbal, and Arithmetic), reliable differences in rated annoyingness of the noises were related to the task category and to the type of noise (jet or helicopter).

  2. The effect of anthropogenic arsenic contamination on the earthworm microbiome.

    PubMed

    Pass, Daniel Antony; Morgan, Andrew John; Read, Daniel S; Field, Dawn; Weightman, Andrew J; Kille, Peter

    2015-06-01

    Earthworms are globally distributed and perform essential roles for soil health and microbial structure. We have investigated the effect of an anthropogenic contamination gradient on the bacterial community of the keystone ecological species Lumbricus rubellus through utilizing 16S rRNA pyrosequencing for the first time to establish the microbiome of the host and surrounding soil. The earthworm-associated microbiome differs from the surrounding environment which appears to be a result of both filtering and stimulation likely linked to the altered environment associated with the gut micro-habitat (neutral pH, anoxia and increased carbon substrates). We identified a core earthworm community comprising Proteobacteria (∼50%) and Actinobacteria (∼30%), with lower abundances of Bacteroidetes (∼6%) and Acidobacteria (∼3%). In addition to the known earthworm symbiont (Verminephrobacter sp.), we identified a potential host-associated Gammaproteobacteria species (Serratia sp.) that was absent from soil yet observed in most earthworms. Although a distinct bacterial community defines these earthworms, clear family- and species-level modification were observed along an arsenic and iron contamination gradient. Several taxa observed in uncontaminated control microbiomes are suppressed by metal/metalloid field exposure, including eradication of the hereto ubiquitously associated Verminephrobacter symbiont, which raises implications to its functional role in the earthworm microbiome.

  3. The effects of noise on performance

    NASA Astrophysics Data System (ADS)

    Suter, Alice H.

    1989-06-01

    The effects of noise on task performance are quite complex, and not as predictable as other noise effects. They are often affected by non-acoustical factors, such as biological and psychological state, as well as external factors such as task complexity and the presence of other stressors. This report describes the rationale and some of the problems inherent in noise and performance research, as well as theories on the mechanisms of effects, and summarizes the various effects. Research on noise and vision suggests some effects from high noise levels on thresholds of sensitivity, critical flicker fusion, and visual field shifts. Small but reliable effects have been demonstrated on vestibular function, expecially with asymmetric exposures. Motor performance usually adapts with repeated or prolonged exposure, but high noise levels can show persistent decrements. Some startle responses, notably the eye-blink response, do not habituate. With respect to task variables, noise has little effect on simple tasks, and can even improve performance on monotonous tasks. Tasks requiring continuous performance may be disrupted, especially by noise levels over 100 dB and if the job requires a high level of sustained performance. Intellectual function is not usually affected, but vigilance tasks are susceptible to noise, particularly under certain conditions. Complex tasks requiring more than one activity are much more likely to be disrupted than simple tasks.

  4. Contribution of seasonal presence of cetaceans, earthquakes, drifting icebergs and anthropogenic activity to the ambient noise level in the Southern Indian Ocean

    NASA Astrophysics Data System (ADS)

    Tsang-Hin-Sun, Eve; Royer, Jean-Yves

    2015-04-01

    Assessing the ambient sound level in the oceans is essential for a better understanding of the interactions between the ecosystem and anthropogenic activities. Ambient noise studies conducted in the North Pacific and Atlantic oceans, have shown that since the 60's oceanic noise level increases with the ship traffic, even if potential impacts of shipping noise on the ecosystem is not yet fully understood. However long-term acoustic records for the Indian Ocean are still limited. Here we present long-term statistics on the ambient sound in the Southern Indian Ocean basin based on 2 years of data collected at 5 widely distributed autonomous hydrophones. The data consist of single hydrophone spectra (10-100 Hz in 1-Hz bins) averaged using Welch's method over 200 s. Spectral probability distributions of the ambient sound level are analyzed in order to identify the main sound sources and their geographical and time variability. The mean sound level within the array is 10 to 20 dB lower than in other oceans, revealing a weaker influence of shipping on the Southern Indian Ocean noise budget. Seismic events are evenly distributed in time and space and mostly contribute to the general low-frequency background noise. Periodic signals are mainly associated with the seasonal presence of 3 types of blue whales and fin whales whose signatures are easily identified at target frequencies. Winter lows and summer highs of the ambient noise levels are also well correlated with ice volume variations. Icebergs are found to be a major sound source, strongly contributing to seasonal variations even at northernmost sites of the array. Although anthropogenic factors do not seem to dominate the noise spectrum, shipping sounds are present north and east of the array. Observed higher sound levels are consistent with the proximity of major traffic lanes.

  5. Playback Experiments for Noise Exposure.

    PubMed

    Holles, Sophie; Simpson, Stephen D; Lecchini, David; Radford, Andrew N

    2016-01-01

    Playbacks are a useful tool for conducting well-controlled and replicated experiments on the effects of anthropogenic noise, particularly for repeated exposures. However, playbacks are unlikely to fully reproduce original sources of anthropogenic noise. Here we examined the sound pressure and particle acceleration of boat noise playbacks in a field experiment and reveal that although there remain recognized limitations, the signal-to-noise ratios of boat playbacks to ambient noise do not exceed those of a real boat. The experimental setup tested is therefore of value for use in experiments on the effects of repeated exposure of aquatic animals to boat noise.

  6. No evidence for an effect of traffic noise on the development of the corticosterone stress response in an urban exploiter.

    PubMed

    Angelier, Frédéric; Meillère, Alizée; Grace, Jacquelyn K; Trouvé, Colette; Brischoux, François

    2016-06-01

    Anthropogenic noise can have important physiological and behavioral effects on wild animals. For example, urban noise could lead to a state of chronic stress and could alter the development of the hypothalamus-pituitary-adrenal (HPA) axis. Supporting this hypothesis, several studies have found that human disturbance is associated with increased circulating corticosterone (CORT) levels. However, it remains unclear whether increased CORT levels are the result of anthropogenic noise or other anthropogenic factors. Here, we experimentally tested the impact of urban noise on the CORT stress response in an urban exploiter (the house sparrow, Passer domesticus) by exposing chicks to a traffic noise ('disturbed chicks') or not ('control chicks'). If noise exposure has a negative impact on developing chicks, we predicted that (1) disturbed chicks will grow slower, will be in poorer condition, and will have a lower fledging probability than controls; (2) disturbed chicks will have higher baseline CORT levels than control; (3) the CORT stress response will be affected by this noise exposure. Contrary to these predictions, we found no effect of our experiment on growth, body condition, and fledging success, suggesting that house sparrow chicks were not negatively affected by this noise exposure. Moreover, we did not find any effect of noise exposure on either baseline CORT levels or the CORT stress response of chicks. This suggests not only that house sparrow chicks did not perceive this noise as stressful, but also that the development of the HPA axis was not affected by such noise exposure. Our study suggests that, contrary to urban avoiders, urban exploiters might be relatively insensitive to urban noise during their development. Further comparative studies are now needed to understand whether such insensitivity to anthropogenic noise is a consistent phenomenon in urban exploiters and whether this is a major requirement of an urban way of life.

  7. Teratogenic effects of noise in mice

    NASA Astrophysics Data System (ADS)

    Murata, M.; Takigawa, H.

    1989-07-01

    This study was undertaken to assess the hazardous effects of noise on embryonic development. The experiment was composed of two parts; one was the observation of the effect due to noise alone, and the other was the observation of the combined effect of noise and known teratogens. ICR mice were exposed to a wide octave-band noise at 100 dB(C) for 6 hours a day in three ways: the first group was exposed to a continuous noise only on day 7 of pregnancy (group "N"), the second was exposed to an intermittent noise (15 min ON/15 min OFF) only on day 7 of pregnancy (group "IN"), and the third was exposed daily to a continuous noise during days 7-12 of pregnancy (group "RN"). Cadmium sulfate or trypan blue was applied as a teratogen, and was administered intraperitoneously on day 7 of pregnancy. On day 18 of pregnancy, mice were sacrificed and the developmental status and external malformations of their fetuses were examined. Each type of noise exposure did not significantly induce embryolethality and fetal growth retardation. However, teratogenicity was observed in groups "N" and "IN". Combined effects of teratogen and noise did not show clear-cut interactions.

  8. Nuisance levels of noise effects radiologists' performance

    NASA Astrophysics Data System (ADS)

    McEntee, Mark F.; Coffey, Amina; Ryan, John; O'Beirne, Aaron; Toomey, Rachel; Evanoff, Micheal; Manning, David; Brennan, Patrick C.

    2010-02-01

    This study aimed to measure the sound levels in Irish x-ray departments. The study then established whether these levels of noise have an impact on radiologists performance Noise levels were recorded 10 times within each of 14 environments in 4 hospitals, 11 of which were locations where radiologic images are judged. Thirty chest images were then presented to 26 senior radiologists, who were asked to detect up to three nodular lesions within 30 posteroanterior chest x-ray images in the absence and presence of noise at amplitude demonstrated in the clinical environment. The results demonstrated that noise amplitudes rarely exceeded that encountered with normal conversation with the maximum mean value for an image-viewing environment being 56.1 dB. This level of noise had no impact on the ability of radiologists to identify chest lesions with figure of merits of 0.68, 0.69, and 0.68 with noise and 0.65, 0.68, and 0.67 without noise for chest radiologists, non-chest radiologists, and all radiologists, respectively. the difference in their performance using the DBM MRMC method was significantly better with noise than in the absence of noise at the 90% confidence interval (p=0.077). Further studies are required to establish whether other aspects of diagnosis are impaired such as recall and attention and the effects of more unexpected noise on performance.

  9. Effect of noise on higher nervous activity

    NASA Astrophysics Data System (ADS)

    Saito, K.

    1988-12-01

    The effects of continuous, regular and irregular intermittent white noises consisting of three kinds of unpleasant noises (frying pan noise (FN), synthesizer noise (SN) and white noise (WN)), pure tones of 125, 250, 500, 1k, 2k, 4k and 8k Hz, and band-limited noises with the same center frequencies as pure tones were estimated by using electroencephalograms (EEG) and auditory evoked potential (AEP), to make clear the relationship between the unpleasantness of noise and brain activity. The results obtained were as follows. Alpha-wave appearance rate differed in continuous, regular and irregular intermittent white noise exposures. Psychologically unpleasant noises, estimated by the method of paired comparisons and a rating scale, brought about changes in brain waves that corresponded to the degree of unpleasantness. Changes in the number and the total power of the peak frequency in brain waves of the subjects exposed to pure tones showed a tendency to be similar to the equal loudness contour. Changes in the AEP components of N 1 and P 2 latencies and P 2 amplitude due to both pure tones and band noises with the same center frequency as each pure tone showed the same pattern, with the shortest latency and amplitude between the frequencies of 1 kHz and 2 kHz. The changes in AEP were also similar to the equal loudness contour.

  10. A synthesis of two decades of research documenting the effects of noise on wildlife.

    PubMed

    Shannon, Graeme; McKenna, Megan F; Angeloni, Lisa M; Crooks, Kevin R; Fristrup, Kurt M; Brown, Emma; Warner, Katy A; Nelson, Misty D; White, Cecilia; Briggs, Jessica; McFarland, Scott; Wittemyer, George

    2016-11-01

    Global increases in environmental noise levels - arising from expansion of human populations, transportation networks, and resource extraction - have catalysed a recent surge of research into the effects of noise on wildlife. Synthesising a coherent understanding of the biological consequences of noise from this literature is challenging. Taxonomic groups vary in auditory capabilities. A wide range of noise sources and exposure levels occur, and many kinds of biological responses have been observed, ranging from individual behaviours to changes in ecological communities. Also, noise is one of several environmental effects generated by human activities, so researchers must contend with potentially confounding explanations for biological responses. Nonetheless, it is clear that noise presents diverse threats to species and ecosystems and salient patterns are emerging to help inform future natural resource-management decisions. We conducted a systematic and standardised review of the scientific literature published from 1990 to 2013 on the effects of anthropogenic noise on wildlife, including both terrestrial and aquatic studies. Research to date has concentrated predominantly on European and North American species that rely on vocal communication, with approximately two-thirds of the data set focussing on songbirds and marine mammals. The majority of studies documented effects from noise, including altered vocal behaviour to mitigate masking, reduced abundance in noisy habitats, changes in vigilance and foraging behaviour, and impacts on individual fitness and the structure of ecological communities. This literature survey shows that terrestrial wildlife responses begin at noise levels of approximately 40 dBA, and 20% of papers documented impacts below 50 dBA. Our analysis highlights the utility of existing scientific information concerning the effects of anthropogenic noise on wildlife for predicting potential outcomes of noise exposure and implementing

  11. Cardiovascular effects of environmental noise exposure

    PubMed Central

    Münzel, Thomas; Gori, Tommaso; Babisch, Wolfgang; Basner, Mathias

    2014-01-01

    The role of noise as an environmental pollutant and its impact on health are being increasingly recognized. Beyond its effects on the auditory system, noise causes annoyance and disturbs sleep, and it impairs cognitive performance. Furthermore, evidence from epidemiologic studies demonstrates that environmental noise is associated with an increased incidence of arterial hypertension, myocardial infarction, and stroke. Both observational and experimental studies indicate that in particular night-time noise can cause disruptions of sleep structure, vegetative arousals (e.g. increases of blood pressure and heart rate) and increases in stress hormone levels and oxidative stress, which in turn may result in endothelial dysfunction and arterial hypertension. This review focuses on the cardiovascular consequences of environmental noise exposure and stresses the importance of noise mitigation strategies for public health. PMID:24616334

  12. The Effect of Human Activities and Their Associated Noise on Ungulate Behavior

    PubMed Central

    Brown, Casey L.; Hardy, Amanda R.; Barber, Jesse R.; Fristrup, Kurt M.; Crooks, Kevin R.; Angeloni, Lisa M.

    2012-01-01

    Background The effect of anthropogenic noise on terrestrial wildlife is a relatively new area of study with broad ranging management implications. Noise has been identified as a disturbance that has the potential to induce behavioral responses in animals similar to those associated with predation risk. This study investigated potential impacts of a variety of human activities and their associated noise on the behavior of elk (Cervus elaphus) and pronghorn (Antilocapra americana) along a transportation corridor in Grand Teton National Park. Methodology/Principal Findings We conducted roadside scan surveys and focal observations of ungulate behavior while concurrently recording human activity and anthropogenic noise. Although we expected ungulates to be more responsive with greater human activity and noise, as predicted by the risk disturbance hypothesis, they were actually less responsive (less likely to perform vigilant, flight, traveling and defensive behaviors) with increasing levels of vehicle traffic, the human activity most closely associated with noise. Noise levels themselves had relatively little effect on ungulate behavior, although there was a weak negative relationship between noise and responsiveness in our scan samples. In contrast, ungulates did increase their responsiveness with other forms of anthropogenic disturbance; they reacted to the presence of pedestrians (in our scan samples) and to passing motorcycles (in our focal observations). Conclusions These findings suggest that ungulates did not consistently associate noise and human activity with an increase in predation risk or that they could not afford to maintain responsiveness to the most frequent human stimuli. Although reduced responsiveness to certain disturbances may allow for greater investment in fitness-enhancing activities, it may also decrease detections of predators and other environmental cues and increase conflict with humans. PMID:22808175

  13. Effects of road traffic background noise on judgments of individual airplane noises. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1979-01-01

    Two laboratory experiments were conducted to investigate the effects of road-traffic background noise on judgments of individual airplane flyover noises. In the first experiment, 27 subjects judged a set of 16 airplane flyover noises in the presence of traffic-noise sessions of 30-min duration consisting of the combinations of 3 traffic-noise types and 3 noise levels. In the second experiment, 24 subjects judged the same airplane flyover noises in the presence of traffic-noise sessions of 10-min duration consisting of the combinations of 2 traffic-noise types and 4 noise levels. In both experiments the airplane noises were judged less annoying in the presence of high traffic-noise levels than in the presence of low traffic-noise levels.

  14. Effect of measurement noise on Granger causality

    NASA Astrophysics Data System (ADS)

    Nalatore, Hariharan; N, Sasikumar; Rangarajan, Govindan

    2014-12-01

    Most of the signals recorded in experiments are inevitably contaminated by measurement noise. Hence, it is important to understand the effect of such noise on estimating causal relations between such signals. A primary tool for estimating causality is Granger causality. Granger causality can be computed by modeling the signal using a bivariate autoregressive (AR) process. In this paper, we greatly extend the previous analysis of the effect of noise by considering a bivariate AR process of general order p . From this analysis, we analytically obtain the dependence of Granger causality on various noise-dependent system parameters. In particular, we show that measurement noise can lead to spurious Granger causality and can suppress true Granger causality. These results are verified numerically. Finally, we show how true causality can be recovered numerically using the Kalman expectation maximization algorithm.

  15. Effect of measurement noise on Granger causality.

    PubMed

    Nalatore, Hariharan; Sasikumar, N; Rangarajan, Govindan

    2014-12-01

    Most of the signals recorded in experiments are inevitably contaminated by measurement noise. Hence, it is important to understand the effect of such noise on estimating causal relations between such signals. A primary tool for estimating causality is Granger causality. Granger causality can be computed by modeling the signal using a bivariate autoregressive (AR) process. In this paper, we greatly extend the previous analysis of the effect of noise by considering a bivariate AR process of general order p. From this analysis, we analytically obtain the dependence of Granger causality on various noise-dependent system parameters. In particular, we show that measurement noise can lead to spurious Granger causality and can suppress true Granger causality. These results are verified numerically. Finally, we show how true causality can be recovered numerically using the Kalman expectation maximization algorithm.

  16. Noise effects in two different biological systems

    NASA Astrophysics Data System (ADS)

    Spagnolo, B.; Spezia, S.; Curcio, L.; Pizzolato, N.; Fiasconaro, A.; Valenti, D.; Lo Bue, P.; Peri, E.; Colazza, S.

    2009-05-01

    We investigate the role of the colored noise in two biological systems: (i) adults of Nezara viridula (L.) (Heteroptera: Pentatomidae), and (ii) polymer translocation. In the first system we analyze, by directionality tests, the response of N. viridula individuals to subthreshold signals plus noise in their mating behaviour. The percentage of insects that react to the subthreshold signal shows a nonmonotonic behaviour, characterized by the presence of a maximum, as a function of the noise intensity. This is the signature of the non-dynamical stochastic resonance phenomenon. By using a “soft” threshold model we find that the maximum of the input-output cross correlation occurs in the same range of noise intensity values for which the behavioural activation of the insects has a maximum. Moreover this maximum value is lowered and shifted towards higher noise intensities, compared to the case of white noise. In the second biological system the noise driven translocation of short polymers in crowded solutions is analyzed. An improved version of the Rouse model for a flexible polymer is adopted to mimic the molecular dynamics by taking into account both the interactions between adjacent monomers and the effects of a Lennard-Jones potential between all beads. The polymer dynamics is simulated in a two-dimensional domain by numerically solving the Langevin equations of motion in the presence of thermal fluctuations and a colored noise source. At low temperatures or for strong colored noise intensities the translocation process of the polymer chain is delayed. At low noise intensity, as the polymer length increases, we find a nonmonotonic behaviour for the mean first translocation time of the polymer centre of inertia. We show how colored noise influences the motion of short polymers, by inducing two different regimes of translocation in the dynamics of molecule transport.

  17. Noise effects on reproduction— animal experiments

    NASA Astrophysics Data System (ADS)

    Takigawa, H.; Sakamoto, H.; Murata, M.; Matsumura, Y.

    1988-12-01

    Noise effects on fetal development were observed in animals. While the copulatory function was not affected, birth rate decreased when the animals were exposed to noise. An increased number of stunted fetuses was observed when the animals were intermittently exposed. However, malformations in the fetuses increased with exposure to both intermittent and continuous noise. Two phases of hormonal change were observed in connection with noise exposure. One is the initial response phase, characterized by the increment of 11-OHCS in the adrenal gland. The other is the end phenomena phase, characterized by a disorder in central control. It is discussed that the disturbance of fetal development by exposure to noise is related to these changes in the hormonal condition.

  18. DISCRIMINATING THE BENTHIC EFFECTS OF ANTHROPOGENIC POINT SOURCES FROM SALINITY AND NITROGEN LOADING

    EPA Science Inventory

    To evaluate the influence of anthropogenic point sources on estuarine systems, environmental managers must be able to discern the level and effects of significant natural factors and nonpoint source inputs. We compared benthic community state, salinity and dissolved inorganic nit...

  19. The effects of extended exposure to traffic noise on parid social and risk-taking behavior.

    PubMed

    Owens, Jessica L; Stec, Courtney L; O'Hatnick, Amy

    2012-09-01

    Traffic noise is a prevalent and yet poorly understood anthropogenic disturbance associated with reduced avian diversity, population densities and pairing and mating success. How these systems are affected is not clear as a direct experimental link between noise and behavior underlying these patterns is missing. Here we provide the first empirical evidence of the effects of long-term exposure to simulated traffic noise on social and risk-taking behavior of Carolina chickadees (Poecile carolinensis) and tufted titmice (Baeolophus bicolor). In testing for these effects we compare two hypotheses regarding the effects of noise on behavior. We found that noise increases sociality by reducing nearest neighbor distances and increasing the number of close-perches within study flocks. These behavioral responses mimic those of species in high-risk situations, such as birds in the presence of a predator. These results provide support for the 'Increased Threat Hypothesis,' which argues that chronic traffic noise affects behavior by increasing the perceived level of threat. Although the adaptive value or function of these responses to noise is unknown, they may serve to mitigate any negative effects of traffic noise. If true, species lacking behavioral plasticity may be more susceptible to effects of traffic noise and other similar acoustic disturbances.

  20. Effects of noise levels and call types on the source levels of killer whale calls.

    PubMed

    Holt, Marla M; Noren, Dawn P; Emmons, Candice K

    2011-11-01

    Accurate parameter estimates relevant to the vocal behavior of marine mammals are needed to assess potential effects of anthropogenic sound exposure including how masking noise reduces the active space of sounds used for communication. Information about how these animals modify their vocal behavior in response to noise exposure is also needed for such assessment. Prior studies have reported variations in the source levels of killer whale sounds, and a more recent study reported that killer whales compensate for vessel masking noise by increasing their call amplitude. The objectives of the current study were to investigate the source levels of a variety of call types in southern resident killer whales while also considering background noise level as a likely factor related to call source level variability. The source levels of 763 discrete calls along with corresponding background noise were measured over three summer field seasons in the waters surrounding the San Juan Islands, WA. Both noise level and call type were significant factors on call source levels (1-40 kHz band, range of 135.0-175.7 dB(rms) re 1 [micro sign]Pa at 1 m). These factors should be considered in models that predict how anthropogenic masking noise reduces vocal communication space in marine mammals.

  1. India heat wave attribution considering effects of anthropogenic aerosols.

    NASA Astrophysics Data System (ADS)

    Haustein, Karsten; Otto, Friederike; Allen, Myles; Cullen, Heidi

    2017-04-01

    Extreme weather event attribution, now a well-established field within the Detection and Attribution community, slowly incorporates all regions of the globe. Here we present heat wave results for India in 2015, using pre-conditioned (SST driven) large ensemble RCM simulations provided by weather@home. Apart from the presentation of a thoroughly validated set of hydrometeorological model variables for the South Asian region, the novelty in this study is that we include a GHG-only ensemble in our analysis. Rather than relying on actual and counterfactual data for 2015 to investigate the event-specific dynamic contribution, we make also use of an ensemble where the SST forcing corresponds to a world in which anthropogenic aerosols have been removed (AA). Since AAs have far-reaching implications for the Asian monsoon system (e.g. Bollasina et al. 2011; Li et al 2016), the changing risk of certain extreme weather events occurring due to a variable load of AAs can potentially be attributed for the first time. Since we are now in the possession a fully consistent 30 year climatology (200 ensemble member per year) for actual, counterfactual and GHG only conditions as well, we can try and answer the question whether circulation changes or trends due to anthropogenic climate change are detectable already. In addition, we demonstrate how these results can be used in our fast track attribution framework, including evidence for the robustness of the analogue method utilised to determine event-specific dynamic contributions.

  2. Exploring noise effects in chaotic optical networks

    NASA Astrophysics Data System (ADS)

    Rasheed, Banaz O.; Abdalah, Sora F.; Al Naimee, Kais A. M.; Al Hasani, Mahdi H.; Aljaff, Parekhan M.; Meucci, Riccardo; Arecchi, F. Titto

    We report the experimental evidence coherence and stochastic resonance in a dynamics of fast chaotic spiking of a semiconductor laser with optical feedback using an external nonwhite noise in the pumping current. We characterize both coherence and stochastic resonance in the time and frequency domain. We show that the regularity of the chaotic pulses in the intensity of laser diod increases when adding noise and it is optimal for some intermediate value of the noise intensity. We find that the power spectrum of the signal develops a peak at a finite frequency at intermediate values of the noise. The results show that noise may help in extracting the periodic signal without synchronization in chaotic communication. Then we reported the effect of external noise numerically on a single system by using bifurcation diagram. Finally, we considered Chaos synchronization in a network of 28 distinct chaotic systems with independent initial conditions when a normal Gaussian noise is added. The transition between non-synchronization to synchronization states using a suitable spatio-temporal representation has been reported. The role of coherence has also been considered.

  3. Anthropogenic effects on winter behavior of ferruginous hawks

    USGS Publications Warehouse

    Plumpton, D.L.; Andersen, D.E.

    1998-01-01

    Little information is known about the ecology of ferruginous hawks (Buteo regalis) in winter versus the breeding season and less about how the species adapts to fragmented grassland habitats. Accordingly, we studied the behavior of 38 radiotagged ferruginous hawks during 3 winters from 1992 to 1995. We used 2 adjacent sites in Colorado that were characterized by low and high levels of anthropogenic influence and habitat fragmentation: the Rocky Mountain Arsenal National Wildlife Refuge (RMANWR; low-level influence), and several adjacent Denver suburbs (high-level influence). Relative abundance of ferruginous hawks differed by treatment area and year (P 0.05) at RMANWR and suburban sites. Ferruginous hawks appear to modify their behavior in fragmented, largely human-altered habitats, provided some foraging habitats with adequate populations of suitable prey species are present.

  4. Estimation of Anthropogenic Heat Emissions in Delhi, India and Their Role in Urban Heat Island Effect

    NASA Astrophysics Data System (ADS)

    Bhati, S.; Mohan, M.

    2016-12-01

    Energy consumption in the urban environment impacts the urban surface energy budget and leads to the emission of anthropogenic sensible heat into the atmosphere. Anthropogenic heat (AH) can vary both in time and space, and are not readily measured. In present study, anthropogenic heat emissions have been estimated using an inventory approach for Delhi. The main sources that have been considered are electricity consumption, vehicular emissions, fuel consumption in domestic sector and waste heat from power plants. Total estimated anthropogenic heat is apportioned gridwise (2 km2) and incorporated in the WRF (version 3.5) model coupled with single-layer Urban canopy model (UCM) to assess the impact of these emissions on urban heat island effect in Delhi. Vehicular emissions have been found to be highest contributor to anthropogenic heat emissions (47%) followed by electricity consumption (28%), domestic fuel consumption (16%) and waste heat from power plants (9%). Highest annual average anthropogenic heat flux was estimated to be 25.2 Wm-2. High flux zones are observed in east Delhi and densely occupied and commercial zones of Sitaram Bazar and Connaught Place. Inclusion of anthropogenic heat emissions in the model improves model performance for near surface temperature as well as urban heat island intensities. Maximum simulated night-time UHI improves from 5.95°C (without AH) to 6.24°C (with AH) against observed value of 6.68°C, thereby indicating positive contribution of anthropogenic heat emissions along with urban canopy towards UHI effect in Delhi. Similarly, spatial distribution and UHI hotspots are found to be comparatively closer to corresponding observed distribution and hotspots with anthropogenic heat emissions being added to the WRF model. Overall, relatively improved model performance is indicative of the impact of anthropogenic heat emissions in local urban meteorology and urban heat island effect in Delhi. Hence, rising population and change in land

  5. Nonlinear effects of anthropogenic aerosol and urban land surface forcing on spring climate in eastern China

    NASA Astrophysics Data System (ADS)

    Deng, Jiechun; Xu, Haiming; Zhang, Leying

    2016-05-01

    Anthropogenic aerosols and urban land cover change induce opposite thermal effects on the atmosphere near surface as well as in the troposphere. One can think of these anthropogenic effects as composed of two parts: the individual effect due to an individual anthropogenic forcing and the nonlinear effects resulting from the coexistence of two forcing factors. In this study, we explored the role of such nonlinear effects in affecting East Asian climate, as well as individual forcing effects, using the Community Atmosphere Model version 5.1 coupled with the Community Land Model version 4. Atmospheric responses were simulated by including anthropogenic aerosol emission only, urban cover only, or the combination of the two, over eastern China. Results showed that nonlinear responses were different from any effects by an individual forcing or the linear combination of individual responses. The nonlinear interaction could generate cold horizontal temperature advection to cool the troposphere, which induced anomalous subsidence along the Yangtze River Valley (YRV). This anomalous vertical motion, together with a weakened low-level southwesterly, favored below-normal (above-normal) rainfall over the YRV (southern China), shifting the spring rain belt southward. The resultant diabatic cooling, in turn, amplified the anomalous descent and further decreased tropospheric temperature over the YRV, forming a positive feedback loop to maintain the nonlinear effects. Consequently, the nonlinear effects acted to reduce the climate anomalies from a simple linear combination of two individual effects and played an important role in regional responses to one anthropogenic forcing when the other is prescribed.

  6. Effects of traffic noise on tree frog stress levels, immunity, and color signaling.

    PubMed

    Troïanowski, Mathieu; Mondy, Nathalie; Dumet, Adeline; Arcanjo, Caroline; Lengagne, Thierry

    2017-10-01

    During the last decade, many studies have focused on the detrimental effects of noise pollution on acoustic communication. Surprisingly, although it is known that noise exposure strongly influences health in humans, studies on wildlife remain scarce. In order to gain insight into the consequences of traffic noise exposure, we experimentally manipulated traffic noise exposure as well as the endocrine status of animals to investigate physiological and phenotypic consequences of noise pollution in an anuran species. We showed that noise exposure increased stress hormone level and induced an immunosuppressive effect. In addition, both traffic noise exposure and stress hormone application negatively impacted H. arborea vocal sac coloration. Moreover, our results suggest profound changes in sexual selection processes because the best quality males with initial attractive vocal sac coloration were the most impacted by noise. Hence, our study suggests that the recent increases in anthropogenic noise worldwide might affect a broader range of animal species than previously thought, because of alteration of visual signals and immunity. Generalizing these results to other taxa is crucial for the conservation of biodiversity in an increasingly noisy world. © 2017 Society for Conservation Biology.

  7. The 'shell effect': music from environmental noise

    NASA Astrophysics Data System (ADS)

    Diodati, Paolo

    2005-02-01

    The 'shell effect' can be used to play music with a pleasant and characteristic timbre. If you place a sensitive microphone at the rim of pipes of suitable length and diameter to obtain resonance frequencies, ambient noise will produce musical notes. The corresponding optical effect, i.e. extracting visible light from ambient radiation considered dark by the human eye, is also discussed.

  8. Bird song and anthropogenic noise: vocal constraints may explain why birds sing higher-frequency songs in cities

    PubMed Central

    Nemeth, Erwin; Pieretti, Nadia; Zollinger, Sue Anne; Geberzahn, Nicole; Partecke, Jesko; Miranda, Ana Catarina; Brumm, Henrik

    2013-01-01

    When animals live in cities, they have to adjust their behaviour and life histories to novel environments. Noise pollution puts a severe constraint on vocal communication by interfering with the detection of acoustic signals. Recent studies show that city birds sing higher-frequency songs than their conspecifics in non-urban habitats. This has been interpreted as an adaptation to counteract masking by traffic noise. However, this notion is debated, for the observed frequency shifts seem to be less efficient at mitigating noise than singing louder, and it has been suggested that city birds might use particularly high-frequency song elements because they can be produced at higher amplitudes. Here, we present the first phonetogram for a songbird, which shows that frequency and amplitude are strongly positively correlated in the common blackbird (Turdus merula), a successful urban colonizer. Moreover, city blackbirds preferentially sang higher-frequency elements that can be produced at higher intensities and, at the same time, happen to be less masked in low-frequency traffic noise. PMID:23303546

  9. Bird song and anthropogenic noise: vocal constraints may explain why birds sing higher-frequency songs in cities.

    PubMed

    Nemeth, Erwin; Pieretti, Nadia; Zollinger, Sue Anne; Geberzahn, Nicole; Partecke, Jesko; Miranda, Ana Catarina; Brumm, Henrik

    2013-03-07

    When animals live in cities, they have to adjust their behaviour and life histories to novel environments. Noise pollution puts a severe constraint on vocal communication by interfering with the detection of acoustic signals. Recent studies show that city birds sing higher-frequency songs than their conspecifics in non-urban habitats. This has been interpreted as an adaptation to counteract masking by traffic noise. However, this notion is debated, for the observed frequency shifts seem to be less efficient at mitigating noise than singing louder, and it has been suggested that city birds might use particularly high-frequency song elements because they can be produced at higher amplitudes. Here, we present the first phonetogram for a songbird, which shows that frequency and amplitude are strongly positively correlated in the common blackbird (Turdus merula), a successful urban colonizer. Moreover, city blackbirds preferentially sang higher-frequency elements that can be produced at higher intensities and, at the same time, happen to be less masked in low-frequency traffic noise.

  10. Climate effects of anthropogenic aerosols over East Asia based on modeling study

    NASA Astrophysics Data System (ADS)

    Mukai, Makiko

    The increasing emission of anthropogenic aerosols causes serious air pollution episodes and various effects on the climate by the aerosols interacting with the radiation budget by directly absorbing and scattering the solar radiation, and by them indirectly modifying the optical properties and lifetimes of clouds. In East Asia anthropogenic aerosol concentrations are rapidly increasing. It is therefore necessary to evaluate the sensitivity of anthropogenic aerosols upon the radiative forcing in this region. For this purpose we utilize an atmospheric general circulation model (AGCM) with an aerosol transport and radiation model and an ocean mixed-layer model. The model in this study was a three-dimensional aerosol transport-radiation model (SPRINTARS), driven by the AGCM developed by CCSR (Center for Climate System Research), NIES (National Institute for Environmental Studies), and FRCGC (Frontier Research Center for Global Change). This model incorporates sulfate, carbonaceous, sea salt, and mineral dust aerosols, the first three of which are assumed to acts as cloud condensation nuclei that generate cloud droplets whose number increases with the number of nuclei. We assumed sulfate and carbonaceous aerosol from fuel burning for anthropogenic aerosol. And the model simulations of equilibrium experiments were performed to investigate the impact of anthropogenic aerosols based on present-day emission data and the preindustrial-era emission data. Our simulation results showed that copious anthropogenic aerosol loading causes significant decrease in the surface downward shortwave radiation flux (SDSWRF), which indicates that a direct effect of aerosols has the greatest influence on the surface radiation. It is found from our model simulations that low-level clouds increase but convective clouds decrease due to reduced convective activity caused by surface cooling when anthropogenic aerosol increases. It was also found that the contributions of aerosols to the radiation

  11. Effects of future anthropogenic pollution emissions on global air quality

    NASA Astrophysics Data System (ADS)

    Pozzer, A.; Zimmermann, P.; Doering, U.; van Aardenne, J.; Dentener, F.; Lelieveld, J.

    2012-04-01

    The atmospheric chemistry general circulation model EMAC is used to estimate the impact of anthropogenic emission changes on global and regional air quality in recent and future years (2005, 2010, 2025 and 2050). The emission scenario assumes that population and economic growth largely determine energy consumption and consequent pollution sources ("business as usual"). By comparing with recent observations, it is shown that the model reproduces the main features of regional air pollution distributions though with some imprecision inherent to the coarse horizontal resolution (around 100 km). To identify possible future hot spots of poor air quality, a multi pollutant index (MPI) has been applied. It appears that East and South Asia and the Arabian Gulf regions represent such hotspots due to very high pollutant concentrations. In East Asia a range of pollutant gases and particulate matter (PM2.5) are projected to reach very high levels from 2005 onward, while in South Asia air pollution, including ozone, will grow rapidly towards the middle of the century. Around the Arabian Gulf, where natural PM2.5 concentrations are already high (desert dust), ozone levels will increase strongly. By extending the MPI definition, we calculated a Per Capita MPI (PCMPI) in which we combined population projections with those of pollution emissions. It thus appears that a rapidly increasing number of people worldwide will experience reduced air quality during the first half of the 21st century. It is projected that air quality for the global average citizen in 2050 will be comparable to the average in East Asia in the year 2005.

  12. Forward speed effects on blown flap noise

    NASA Technical Reports Server (NTRS)

    Pennock, A. P.

    1977-01-01

    The effects of forward speed on the noise of under-the-wing (externally blown flaps, EBF) and over-the-wing (upper surface blown, USB) blown flap configurations were measured in wind tunnel model tests with cold jets. The results are presented without correction for the effects (e.g., signal convection, shear layer refraction) associated with flight simulation in a wind tunnel or free jet facility. Noise decreases were generally observed at microphones forward of the wing. The reductions were larger at the low frequencies (below peak SPL) than at the high (above peak SPL). Noise increases of 10 dB or more were observed at the aft microphones, especially in the high frequency range.

  13. Sleep deepening effect of steady pink noise

    NASA Astrophysics Data System (ADS)

    Suzuki, S.; Kawada, T.; Ogawa, M.; Aoki, S.

    1991-12-01

    Sleep under a steady pink noise was studied by a hypnogram of EEG. A young male subject slept all night under a steady pink noise of 40, 50 or 60 dB(A) for 4 to 5 nights, and for 10 nights under unexposed conditions with 35 dB(A). The hypnogram showed a significant decrease in the proportion of REM and an increase in the proportion of stage 2, at 60 dB(A) of steady pink noise exposure. The proportion of stage 3 increased significantly at 40 and 50 dB(A) as compared with 35 dB(A). The average depth of a night's sleep at 60 dB(A), calculated postulating stage W, 1, 2, 3 and 4 to be 0·0, 1·0, 2·0, 3·0 and 4·0, respectively, and REM to be 1·5, was significantly deeper than that at 35 and 40 dB(A). These findings are all sleep deepening effects of a steady noise. A second experiments was carried out with four other subjects exposed to a night of 60 dB(A) of steady pink noise and a paired quiet night. All four subjects also showed a decrease in the proportion of REM and an increase in the proportion of stage 2 at this exposure level. No significant change in subjective sleep was observed in either experiment. An inhibition pulse from the cortex may suppress the activation of reticular formation, which could make sleep under a steady noise deeper. However, the meaning of a depressed proportion of REM under steady pink noise is not clear.

  14. Monitoring of Geoengineering Effects and their Natural and Anthropogenic Analogues

    NASA Astrophysics Data System (ADS)

    Duren, R. M.; Robock, A.; Stephens, G. L.; MacMynowski, D. G.

    2011-12-01

    A number of climate intervention concepts, referred to as "geoengineering," are being considered as an alternative approach to managing climate change. However, before we go down the path of deliberate climate intervention including precursor field-experiments, it is essential that we take the necessary steps to validate our understanding that underpins any of the proposed intervention concepts in order to understand all likely consequences and put in place the necessary strategies for monitoring the expected and unintended consequences of such intervention. The Keck Institute for Space Studies (KISS) is undertaking a project to identify specific priorities for improved scientific understanding and focused efforts to address selected priorities. The KISS project does not advocate the deployment of geoengineering or monitoring systems for potential field experiments but is rather a precautionary study with the following goals: 1) enumeration of where major gaps in our understanding exist in solar radiation management (SRM) approaches, 2) identification of the research that would be required to improve understanding of such impacts including modeling and observation of natural and anthropogenic analogues to geoengineering, and 3) a preliminary assessment of where gaps exist in observations of relevance to SRMs and what is needed to fill such gaps. This study focuses primarily on SRM rather than other proposed geoengineering techniques such as carbon dioxide removal from the atmosphere because there exist a number of analogues to the SRMs that currently operate on Earth that provide a unique opportunity to assess our understanding of the response of the climate system to associated changes in solar radiation. Additionally, the processes related to these analogues are also fundamental to understanding climate change itself being of central relevance to how climate is forced by aerosol and respond through clouds, among other influences (e.g., such research has potential

  15. Effect of temperature on surface noise

    NASA Technical Reports Server (NTRS)

    Olsen, W.; Wasserbauer, C.

    1980-01-01

    An experimental work is discussed whose objective was to obtain data that show the effect of temperature and temperature fluctuations on surface noise. This was accomplished experimentally by immersing a small chord airfoil in the turbulent airstream of a hot jet. The theory and experiment reported by Olsen (1976) provided a guide for designing and validating the hot jet experiment and for interpreting the data. It is shown that increased temperature causes a small decrease in the sound levels; at the same time it causes a shift in the spectra that is smaller but similar to the shift observed with subsonic hot jet noise.

  16. [The effects of noise on health].

    PubMed

    Cabaní, Fernando Tolosa

    2005-02-01

    This article is adapted from the inaugural speech which Dr. Tolosa made to the Royal Academy of Medicine in the Balearic Islands during the 2003 academic year. In his speech, he analyzed how the presence of sound in our environment is such a common factor in our daily lives that we are hardly aware of its effects. Sound provides experiences as pleasant as listening to music or birdsongs, or sound enables oral communication among people; but together with these agreeable auditory perceptions, bothersome, even harmful, noise is also present in our lives; this noise can limit our relationships and affect our health in an irreversible manner.

  17. Noise Effects on Human Performance: A Meta-Analytic Synthesis

    ERIC Educational Resources Information Center

    Szalma, James L.; Hancock, Peter A.

    2011-01-01

    Noise is a pervasive and influential source of stress. Whether through the acute effects of impulse noise or the chronic influence of prolonged exposure, the challenge of noise confronts many who must accomplish vital performance duties in its presence. Although noise has diffuse effects, which are shared in common with many other chronic forms of…

  18. Noise Effects on Human Performance: A Meta-Analytic Synthesis

    ERIC Educational Resources Information Center

    Szalma, James L.; Hancock, Peter A.

    2011-01-01

    Noise is a pervasive and influential source of stress. Whether through the acute effects of impulse noise or the chronic influence of prolonged exposure, the challenge of noise confronts many who must accomplish vital performance duties in its presence. Although noise has diffuse effects, which are shared in common with many other chronic forms of…

  19. Emergency Vehicle Siren Noise Effectiveness

    NASA Astrophysics Data System (ADS)

    D'Angela, Peter

    Navigating safely through traffic, while responding to an emergency, is often a challenge for emergency responders. To help alert other motorists, these responders use emergency lights and/or sirens. However, the former is useful only if within clear visual range of the other drivers. This shortcoming puts a greater emphasis on the importance of the audible emergency siren, which has its own shortcomings. This study considered several emergency siren systems with the goal to determine the most effective siren system(s) based on several criteria. Multiple experimental measurements and subjective analysis using jury testing using an NVH driving simulator were performed. It was found that the traditional mechanical siren was the most effective audible warning device; however, with significantly reduced electrical power requirements, the low frequency Rumbler siren, in conjunction with a more conventional electronic Yelp siren, was the preferred option. Recommendations for future work are also given.

  20. Anthropogenic Aerosol Effects on Sea Surface Temperatures: Mixed-Layer Ocean Experiments with Explicit Aerosol Representation

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Wild, Martin; Knutti, Reto

    2014-05-01

    Anthropogenic aerosols affect the Earth's radiative balance both through direct and indirect effects. These effects can lead to a reduction of the incoming solar radiation at the surface, i.e. dimming, which may lead to a change in sea surface temperatures (SST) or SST pattern. This, in turn, may affect precipitation patterns. The goal of the present work is to achieve an estimate of the equilibrium SST changes under anthropogenic aerosol forcing since industrialisation. We show preliminary results from mixed-layer ocean (MLO) experiments with explicit aerosol representation performed with ECHAM6-HAM. The (fixed) MLO heat flux into the deep ocean was derived from atmosphere only runs with fixed climatological SSTs (1961-1990 average) and present day (year 2000) aerosols and GHG burdens. Some experiments we repeated with an alternative MLO deep ocean heat flux (based on pre-industrial conditions) to test the robustness of our results with regard to this boundary condition. The maximum surface temperature responses towards anthropogenic aerosol and GHG forcing (separately and combined) were derived on a global and regional scale. The same set of experiments was performed with aerosol and GHG forcings representative of different decades over the past one and a half centuries. This allows to assess how SST patterns at equilibrium changed with changing aerosol (and GHG) forcing. Correlating SST responses with the change in downward clear-sky and all-sky shortwave radiation provides a first estimate of the response to anthropogenic aerosols. Our results show a clear contrast in hemispheric surface temperature response, as expected from the inter-hemispheric asymmetry of aerosol forcing The presented work is part of a project aiming at quantifying the effect of anthropogenic aerosol forcing on SSTs and the consequences for global precipitation patterns. Results from this study will serve as a starting point for further experiments involving a dynamic ocean model, which

  1. Climate effects of anthropogenic sulfate: Simulations from a coupled chemistry/climate model

    SciTech Connect

    Chuang, C.C.; Penner, J.E.; Taylor, K.E.; Walton, J.J.

    1993-09-01

    In this paper, we use a more comprehensive approach by coupling a climate model with a 3-D global chemistry model to investigate the forcing by anthropogenic aerosol sulfate. The chemistry model treats the global-scale transport, transformation, and removal of SO{sub 2}, DMS and H{sub 2}SO{sub 4} species in the atmosphere. The mass concentration of anthropogenic sulfate from fossil fuel combustion and biomass burning is calculated in the chemistry model and provided to the climate model where it affects the shortwave radiation. We also investigate the effect, with cloud nucleation parameterized in terms of local aerosol number, sulfate mass concentration and updraft velocity. Our simulations indicate that anthropogenic sulfate may result in important increases in reflected solar radiation, which would mask locally the radiative forcing from increased greenhouse gases. Uncertainties in these results will be discussed.

  2. The Effects of Noise on Performance

    DTIC Science & Technology

    1989-06-01

    appeared to impair short - term memory , and the combined effects of internal auditory and proprioceptive restrictions were additive (Adams Lt al., 1969...D.R. and Jones, D.M. The effects of noise and incentives upon retention in short - term memory . Brit. J_ Psychol-, 6i, 61-68, 1975. Davies, D.R., Lang...produced decrements at least as large as shifts to higher levels on short - term memory and reaction time tasks. The results appeared as a deceleration in

  3. Anthropogenic Moisture production and its effect on boundary-layer circulations over New York City

    Treesearch

    Robert D. Bornstein; Yam-Tong Tam

    1977-01-01

    A heat and moisture excess over New York City is shown to exist by the analysis of helicopter soundings of temperature and wet-bulb depression. The magnitude of the temporal and spatial distribution of anthropogenic moisture emissions in New York City were estimated from fuel-usage data. The URBMET urban boundary-layer model was used to evaluate the effects on the...

  4. The Anthropogenic "Greenhouse Effect": Greek Prospective Primary Teachers' Ideas about Causes, Consequences and Cures

    ERIC Educational Resources Information Center

    Ikonomidis, Simos; Papanastasiou, Dimitris; Melas, Dimitris; Avgoloupis, Stavros

    2012-01-01

    This study explores the ideas of Greek prospective primary teachers about the anthropogenic greenhouse effect, particularly about its causes, consequences and cures. For this purpose, a survey was conducted: 265 prospective teachers completed a closed-form questionnaire. The results showed serious misconceptions in all areas (causes, consequences…

  5. The Anthropogenic "Greenhouse Effect": Greek Prospective Primary Teachers' Ideas about Causes, Consequences and Cures

    ERIC Educational Resources Information Center

    Ikonomidis, Simos; Papanastasiou, Dimitris; Melas, Dimitris; Avgoloupis, Stavros

    2012-01-01

    This study explores the ideas of Greek prospective primary teachers about the anthropogenic greenhouse effect, particularly about its causes, consequences and cures. For this purpose, a survey was conducted: 265 prospective teachers completed a closed-form questionnaire. The results showed serious misconceptions in all areas (causes, consequences…

  6. EVOLUTIONARY AND ECOLOGICAL EFFECTS OF MULTIGENERATIONAL EXPOSURES TO ANTHROPOGENIC STRESSORS

    EPA Science Inventory

    Biological and ecological responses to stress are dictated by duration and frequency, as well as instantaneous magnitude. Conditional compensatory responses at the physiological and behavioral levels, referred to as ?acclimation', may mitigate effects on individuals experiencing ...

  7. EVOLUTIONARY AND ECOLOGICAL EFFECTS OF MULTIGENERATIONAL EXPOSURES TO ANTHROPOGENIC STRESSORS

    EPA Science Inventory

    Biological and ecological responses to stress are dictated by duration and frequency, as well as instantaneous magnitude. Conditional compensatory responses at the physiological and behavioral levels, referred to as ?acclimation', may mitigate effects on individuals experiencing ...

  8. Identifying Variations in Baseline Behavior of Killer Whales (Orcinus orca) to Contextualize Their Responses to Anthropogenic Noise.

    PubMed

    Samarra, Filipa I P; Miller, Patrick J O

    2016-01-01

    Determining the baseline behavior of a whale requires understanding natural variations occurring due to environmental context, such as changes in prey behavior. Killer whales feeding on herring consistently encircle herring schools; however, depth of feeding differs from near the surface in winter to deeper than 10 m in spring and summer. These variations in feeding depth are probably due to the depth of the prey and the balance between the costs and benefits of bringing schools of herring to the surface. Such variation in baseline behavior may incur different energetic costs and consequently change the motivation of whales to avoid a feeding area. Here, we discuss these variations in feeding behavior in the context of exposure to noise and interpret observed responses to simulated navy sonar signals.

  9. Effects of anthropogenic developments on common raven nesting biology in the West Mojave Desert.

    PubMed

    Kristan, William B; Boarman, William I

    2007-09-01

    Subsidized predators may affect prey abundance, distribution, and demography. Common Ravens (Corvus corax) are anthropogenically subsidized throughout their range and, in the Mojave Desert, have increased in number dramatically over the last 3-4 decades. Human-provided food resources are thought to be important drivers of raven population growth, but human developments add other features as well, such as nesting platforms. From 1996 to 2000, we examined the nesting ecology of ravens in the Mojave Desert, relative to anthropogenic developrhent. Ravens nested disproportionately near point sources of food and water subsidies (such as towns, landfills, and ponds) but not near roads (sources of road-killed carrion), even though both sources of subsidy enhanced fledging success. Initiation of breeding activity was more likely when a nest from the previous year was present at the start of a breeding season but was not affected by access to food. The relative effect of environmental modifications on fledging success varied from year to year, but the effect of access to human-provided resources was comparatively consistent, suggesting that humans provide consistently high-quality breeding habitat for ravens. Anthropogenic land cover types in the desert are expected to promote raven population growth and to allow ravens to occupy parts of the desert that otherwise would not support them. Predatory impacts of ravens in the Mojave Desert can therefore be considered indirect effects of anthropogenic development.

  10. Effects of anthropogenic developments on common Raven nesting biology in the west Mojave Desert

    USGS Publications Warehouse

    Kristan, W. B.; Boarman, W.I.

    2007-01-01

    Subsidized predators may affect prey abundance, distribution, and demography. Common Ravens (Corvus corax) are anthropogenically subsidized throughout their range and, in the Mojave Desert, have increased in number dramatically over the last 3-4 decades. Human-provided food resources are thought to be important drivers of raven population growth, but human developments add other features as well, such as nesting platforms. From 1996 to 2000, we examined the nesting ecology of ravens in the Mojave Desert, relative to anthropogenic development. Ravens nested disproportionately near point sources of food and water subsidies (such as towns, landfills, and ponds) but not near roads (sources of road-killed carrion), even though both sources of subsidy enhanced fledging success. Initiation of breeding activity was more likely when a nest from the previous year was present at the start of a breeding season but was not affected by access to food. The relative effect of environmental modifications on fledging success varied from year to year, but the effect of access to humanprovided resources was comparatively consistent, suggesting that humans provide consistently high-quality breeding habitat for ravens. Anthropogenic land cover types in the desert are expected to promote raven population growth and to allow ravens to occupy parts of the desert that otherwise would not support them. Predatory impacts of ravens in the Mojave Desert can therefore be considered indirect effects of anthropogenic development. ?? 2007 by the Ecological Society of America.

  11. Effect of forward motion on engine noise

    NASA Technical Reports Server (NTRS)

    Blankenship, G. L.; Low, J. K. C.; Watkins, J. A.; Merriman, J. E.

    1977-01-01

    Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground.

  12. Effects of aircraft noise on human sleep.

    NASA Technical Reports Server (NTRS)

    Lukas, J. S.

    1972-01-01

    Under controlled conditions in two test rooms, studies were made of the response of sleeping subjects to the stimuli of simulated sonic booms and subsonic jet aircraft noise. Children were relatively nonresponsive to the stimuli. In general, the older the subject, the more likely is behavioral awakening. The response rates to the two types of stimuli were essentially the same. The stimulus intensity had little, if any, effect on frequency of arousal, although other degrees of response did increase.

  13. Effects of aircraft noise on human sleep.

    NASA Technical Reports Server (NTRS)

    Lukas, J. S.

    1972-01-01

    Under controlled conditions in two test rooms, studies were made of the response of sleeping subjects to the stimuli of simulated sonic booms and subsonic jet aircraft noise. Children were relatively nonresponsive to the stimuli. In general, the older the subject, the more likely is behavioral awakening. The response rates to the two types of stimuli were essentially the same. The stimulus intensity had little, if any, effect on frequency of arousal, although other degrees of response did increase.

  14. Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes.

    PubMed

    Kuijper, D P J; Sahlén, E; Elmhagen, B; Chamaillé-Jammes, S; Sand, H; Lone, K; Cromsigt, J P G M

    2016-10-26

    Large carnivores are frequently presented as saviours of biodiversity and ecosystem functioning through their creation of trophic cascades, an idea largely based on studies coming primarily out of relatively natural landscapes. However, in large parts of the world, particularly in Europe, large carnivores live in and are returning to strongly human-modified ecosystems. At present, we lack a coherent framework to predict the effects of large carnivores in these anthropogenic landscapes. We review how human actions influence the ecological roles of large carnivores by affecting their density or behaviour or those of mesopredators or prey species. We argue that the potential for density-mediated trophic cascades in anthropogenic landscapes is limited to unproductive areas where even low carnivore numbers may impact prey densities or to the limited parts of the landscape where carnivores are allowed to reach ecologically functional densities. The potential for behaviourally mediated trophic cascades may be larger and more widespread, because even low carnivore densities affect prey behaviour. We conclude that predator-prey interactions in anthropogenic landscapes will be highly context-dependent and human actions will often attenuate the ecological effects of large carnivores. We highlight the knowledge gaps and outline a new research avenue to study the role of carnivores in anthropogenic landscapes.

  15. Paws without claws? Ecological effects of large carnivores in anthropogenic landscapes

    PubMed Central

    Sahlén, E.; Elmhagen, B.; Chamaillé-Jammes, S.; Sand, H.; Lone, K.; Cromsigt, J. P. G. M.

    2016-01-01

    Large carnivores are frequently presented as saviours of biodiversity and ecosystem functioning through their creation of trophic cascades, an idea largely based on studies coming primarily out of relatively natural landscapes. However, in large parts of the world, particularly in Europe, large carnivores live in and are returning to strongly human-modified ecosystems. At present, we lack a coherent framework to predict the effects of large carnivores in these anthropogenic landscapes. We review how human actions influence the ecological roles of large carnivores by affecting their density or behaviour or those of mesopredators or prey species. We argue that the potential for density-mediated trophic cascades in anthropogenic landscapes is limited to unproductive areas where even low carnivore numbers may impact prey densities or to the limited parts of the landscape where carnivores are allowed to reach ecologically functional densities. The potential for behaviourally mediated trophic cascades may be larger and more widespread, because even low carnivore densities affect prey behaviour. We conclude that predator–prey interactions in anthropogenic landscapes will be highly context-dependent and human actions will often attenuate the ecological effects of large carnivores. We highlight the knowledge gaps and outline a new research avenue to study the role of carnivores in anthropogenic landscapes. PMID:27798302

  16. Linking effects of anthropogenic debris to ecological impacts

    PubMed Central

    Browne, Mark Anthony; Underwood, A. J.; Chapman, M. G.; Williams, Rob; Thompson, Richard C.; van Franeker, Jan A.

    2015-01-01

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the ‘health’, feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. PMID:25904661

  17. Linking effects of anthropogenic debris to ecological impacts.

    PubMed

    Browne, Mark Anthony; Underwood, A J; Chapman, M G; Williams, Rob; Thompson, Richard C; van Franeker, Jan A

    2015-05-22

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the 'health', feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris.

  18. Local noise sensitivity: Insight into the noise effect on chaotic dynamics.

    PubMed

    Sviridova, Nina; Nakamura, Kazuyuki

    2016-12-01

    Noise contamination in experimental data with underlying chaotic dynamics is one of the significant problems limiting the application of many nonlinear time series analysis methods. Although numerous studies have been devoted to the investigation of different aspects of noise-nonlinear dynamics interactions, the effects produced by noise on chaotic dynamics are not fully understood. This study sought to analyze the local effects produced by noise on chaotic dynamics with a smooth attractor. Local Wayland test translation errors were calculated for noise-induced Lorenz and Rössler chaotic models, and for experimental green light photoplethysmogram data. Results demonstrated that under noise induction, local regions on the chaotic attractor with high values of local translation error can be observed. This phenomenon was defined as the local noise sensitivity. It was found that for both models, local noise-sensitive regions were located close to the system's equilibrium points. Additionally, it was found that the reconstructed dynamics represent well the local noise sensitivity of the original dynamics. The concept of local noise sensitivity is expected to contribute to various applied studies, as it reveals regions of chaotic attractors that are sensitive to the presence of noise.

  19. Noise and stress effects on preschool personnel.

    PubMed

    Sjödin, Fredrik; Kjellberg, Anders; Knutsson, Anders; Landström, Ulf; Lindberg, Lennart

    2012-01-01

    The aim of the study was to analyze the presence of stress-related health problems among preschool employees and the way in which these reactions are related to noise and other work parameters. The investigation included 101 employees at 17 preschools in Umeå County, located in northern Sweden. Individual noise recordings and recordings in dining rooms and play halls were made at two departments from each preschool. The adverse effects on the employees were analyzed by use of different validated questionnaires and by saliva cortisol samples. Stress and energy output were pronounced among the employees, and about 30% of the staff experienced strong burnout syndromes. Mental recovery after work was low, indicated by remaining high levels of stress after work. The burnout symptoms were associated with reduced sleep quality and morning sleepiness. Cortisol levels supported the conclusion about pronounced daily stress levels of the preschool employees.

  20. Effect of noise correlations on randomized benchmarking

    NASA Astrophysics Data System (ADS)

    Ball, Harrison; Stace, Thomas M.; Flammia, Steven T.; Biercuk, Michael J.

    2016-02-01

    Among the most popular and well-studied quantum characterization, verification, and validation techniques is randomized benchmarking (RB), an important statistical tool used to characterize the performance of physical logic operations useful in quantum information processing. In this work we provide a detailed mathematical treatment of the effect of temporal noise correlations on the outcomes of RB protocols. We provide a fully analytic framework capturing the accumulation of error in RB expressed in terms of a three-dimensional random walk in "Pauli space." Using this framework we derive the probability density function describing RB outcomes (averaged over noise) for both Markovian and correlated errors, which we show is generally described by a Γ distribution with shape and scale parameters depending on the correlation structure. Long temporal correlations impart large nonvanishing variance and skew in the distribution towards high-fidelity outcomes—consistent with existing experimental data—highlighting potential finite-sampling pitfalls and the divergence of the mean RB outcome from worst-case errors in the presence of noise correlations. We use the filter-transfer function formalism to reveal the underlying reason for these differences in terms of effective coherent averaging of correlated errors in certain random sequences. We conclude by commenting on the impact of these calculations on the utility of single-metric approaches to quantum characterization, verification, and validation.

  1. Effective tactile noise facilitates visual perception.

    PubMed

    Lugo, J E; Doti, R; Faubert, J

    2012-01-01

    The fulcrum principle establishes that a subthreshold excitatory signal (entering in one sense) that is synchronous with a facilitation signal (entering in a different sense) can be increased (up to a resonant-like level) and then decreased by the energy and frequency content of the facilitating signal. As a result, the sensation of the signal changes according to the excitatory signal strength. In this context, the sensitivity transitions represent the change from subthreshold activity to a firing activity in multisensory neurons. Initially the energy of their activity (supplied by the weak signals) is not enough to be detected but when the facilitating signal enters the brain, it generates a general activation among multisensory neurons, modifying their original activity. In our opinion, the result is an integrated activation that promotes sensitivity transitions and the signals are then perceived. In other words, the activity created by the interaction of the excitatory signal (e.g., visual) and the facilitating signal (tactile noise) at some specific energy, produces the capability for a central detection of an otherwise weak signal. In this work we investigate the effect of an effective tactile noise on visual perception. Specifically we show that tactile noise is capable of decreasing luminance modulated thresholds.

  2. Effect of Ship Noise on Sleep

    NASA Astrophysics Data System (ADS)

    Tamura, Y.; Kawada, T.; Sasazawa, Y.

    1997-08-01

    The effects of a steady sound level of 65 dB(A) from a diesel ship engine on nocturnal sleep were studied using polygraphic and subjective sleep parameters. Three healthy men, aged 29 to 33 years, participated in the experiment. Sleep polygrams and the sound level in a sleep laboratory were recorded for each subject for five exposure nights and five control nights. The following morning, the subjects answered a self-rating sleep questionnaire (called the OSA) and underwent simple reaction time tests. The percentage of S2, SREM latency and the REM interval increased, while %SREM decreased during the noise-exposed nights as compared with corresponding values on the control nights. Other parameters of sleep EEG were unchanged. Five scale scores for OSA, sleepiness, sleep maintenance, worry, integrated sleep feeling and sleep initiation deteriorated significantly on the noise-exposed nights as compared with the control nights. Canonical discriminant analysis was conducted using 19 sleep parameters. The standard partial regression coefficients of %SREM, %S2 and %S1 were somewhat higher than other parameters. It was suggested that exposure to the 65 dB(A) ship noise exerted adverse effects on nocturnal sleep, subjectively and in part polygraphically (REM sleep and shallow sleep).

  3. Assessment of management to mitigate anthropogenic effects on large whales.

    PubMed

    Van der Hoop, Julie M; Moore, Michael J; Barco, Susan G; Cole, Timothy V N; Daoust, Pierre-Yves; Henry, Allison G; McAlpine, Donald F; McLellan, William A; Wimmer, Tonya; Solow, Andrew R

    2013-02-01

    United States and Canadian governments have responded to legal requirements to reduce human-induced whale mortality via vessel strikes and entanglement in fishing gear by implementing a suite of regulatory actions. We analyzed the spatial and temporal patterns of mortality of large whales in the Northwest Atlantic (23.5°N to 48.0°N), 1970 through 2009, in the context of management changes. We used a multinomial logistic model fitted by maximum likelihood to detect trends in cause-specific mortalities with time. We compared the number of human-caused mortalities with U.S. federally established levels of potential biological removal (i.e., species-specific sustainable human-caused mortality). From 1970 through 2009, 1762 mortalities (all known) and serious injuries (likely fatal) involved 8 species of large whales. We determined cause of death for 43% of all mortalities; of those, 67% (502) resulted from human interactions. Entanglement in fishing gear was the primary cause of death across all species (n = 323), followed by natural causes (n = 248) and vessel strikes (n = 171). Established sustainable levels of mortality were consistently exceeded in 2 species by up to 650%. Probabilities of entanglement and vessel-strike mortality increased significantly from 1990 through 2009. There was no significant change in the local intensity of all or vessel-strike mortalities before and after 2003, the year after which numerous mitigation efforts were enacted. So far, regulatory efforts have not reduced the lethal effects of human activities to large whales on a population-range basis, although we do not exclude the possibility of success of targeted measures for specific local habitats that were not within the resolution of our analyses. It is unclear how shortfalls in management design or compliance relate to our findings. Analyses such as the one we conducted are crucial in critically evaluating wildlife-management decisions. The results of these analyses can provide

  4. Effects of anthropogenic inputs on the organic quality of urbanized streams.

    PubMed

    Kalscheur, Kathryn N; Penskar, Rebecca R; Daley, Allison D; Pechauer, Shannon M; Kelly, John J; Peterson, Christopher G; Gray, Kimberly A

    2012-05-15

    Due to arid conditions, population growth, and anthropogenic impacts from agricultural and urban development, wastewater effluent makes up an increasingly large percentage of surface water supplies promoting concerns about the potential ecological and human health effects associated with the organic quality of surface waters receiving treated wastewater discharge. Anthropogenic inputs alter the quality and quantity of organic carbon and also affect the ability of aquatic ecosystems to retain or transform carbon and other nutrients. In this paper, we use pyrolysis-GC/MS (Py-GC/MS) as a tool to examine whether the dissolved organic carbon (DOC) in suburban streams influenced by anthropogenic inputs displays an organic signature that is structurally different from natural organic material (NOM). Py-GC/MS was not only able to differentiate among stream sites that received discharge from upstream wastewater treatment plants and those that did not, but also distinguished stream sites influenced significantly by storm water. Distinct organic signatures were evident in stream waters with upstream wastewater treatment plant discharges regardless of the distance from effluent discharge, indicative of the persistent nature of effluent-derived organic material (EfOM). The pyrolysis fragments of 3-methyl-pyridine, 2-methyl-pyridine, pyrrole, and acetamide were identified as indicators of EfOM, supporting previous research that has suggested that protein and aminosugar derivitives are possible wastewater markers. Furthermore, pyrolysis fragments associated with soil polycarboxylic acids correlated highly with stream sites having the least anthropogenic influences.

  5. Anthropogenic effects on global riverine sediment and water discharge - a spatially explicit analysis

    NASA Astrophysics Data System (ADS)

    Cohen, S.; Kettner, A. J.; Syvitski, J. P.

    2013-12-01

    Changes in global riverine water discharge and suspended sediment flux over a 50-year period, 1960-2010 are studied, applying a new version of the WBMsed (WBMsed v.2.0) global hydrological water balance model. A new floodplain component is introduced to better represent water and sediment dynamics during periods of overbank discharge. Validated against data from 16 globally distributed stations, WBMsed v.2.0 simulation results show considerable improvement over the original model. Anthropogenic impact on sediment and water discharge is evaluated by comparing global scale simulations with and without human drivers and parameters (agricultural land use, water intake form aquifers and rivers, sediment trapping in reservoirs, and human-induced soil erosion). The results show that, on average, global riverine sediment flux is reduced by approximately 25% by anthropogenic activities (almost exclusively due to trapping in reservoirs) while water discharge is reduced by about 2%. These results correspond to previous analysis by other research groups. Substantial global and intra-basin variability is observed (see Figure 1) for the first time. In some regions an opposite anthropogenic effect on sediment and water discharge was predicted (e.g. west Mississippi Basin, Rio Grande River, Indian subcontinent). We discuss the western part of the Mississippi Basin as an example of this intriguing anthropogenic impact. Figure 1. Percent change between disturbed and pristine simulations (with and without human footprint respectively) for sediment flux (top) and water discharge (bottom).

  6. Effect of chromatic dispersion on nonlinear phase noise.

    PubMed

    Green, A G; Mitra, P P; Wegener, L G L

    2003-12-15

    We consider the combined effects of amplified spontaneous emission noise, optical Kerr nonlinearity, and chromatic dispersion on phase noise in an optical communication system. The effect of amplified spontaneous emission noise and Kerr nonlinearity were considered previously by Gordon and Mollenauer [Opt. Lett. 15, 1351 (1990)], and the effect of nonlinearity was found to be severe. We investigate the effect of chromatic dispersion on phase noise and show that it can either enhance or suppress the nonlinear noise amplification. For large absolute values of dispersion the nonlinear effect is suppressed, and the phase noise is reduced to its linear value. For a range of negative values of dispersion, however, nonlinear phase noise is enhanced and exhibits a maximum related to the modulation instability found in amplitude fluctuations. Nonlinear phase noise is quenched by these effects even in dispersion-compensated systems; the degree of suppression is sensitively dependent on the dispersion map. We demonstrate these results analytically with a simple linearized model.

  7. Assessment of Management to Mitigate Anthropogenic Effects on Large Whales

    PubMed Central

    Van Der Hoop, Julie M; Moore, Michael J; Barco, Susan G; Cole, Timothy VN; Daoust, Pierre-Yves; Henry, Allison G; McAlpine, Donald F; McLellan, William A; Wimmer, Tonya; Solow, Andrew R

    2013-01-01

    Abstract United States and Canadian governments have responded to legal requirements to reduce human-induced whale mortality via vessel strikes and entanglement in fishing gear by implementing a suite of regulatory actions. We analyzed the spatial and temporal patterns of mortality of large whales in the Northwest Atlantic (23.5°N to 48.0°N), 1970 through 2009, in the context of management changes. We used a multinomial logistic model fitted by maximum likelihood to detect trends in cause-specific mortalities with time. We compared the number of human-caused mortalities with U.S. federally established levels of potential biological removal (i.e., species-specific sustainable human-caused mortality). From 1970 through 2009, 1762 mortalities (all known) and serious injuries (likely fatal) involved 8 species of large whales. We determined cause of death for 43% of all mortalities; of those, 67% (502) resulted from human interactions. Entanglement in fishing gear was the primary cause of death across all species (n = 323), followed by natural causes (n = 248) and vessel strikes (n = 171). Established sustainable levels of mortality were consistently exceeded in 2 species by up to 650%. Probabilities of entanglement and vessel-strike mortality increased significantly from 1990 through 2009. There was no significant change in the local intensity of all or vessel-strike mortalities before and after 2003, the year after which numerous mitigation efforts were enacted. So far, regulatory efforts have not reduced the lethal effects of human activities to large whales on a population-range basis, although we do not exclude the possibility of success of targeted measures for specific local habitats that were not within the resolution of our analyses. It is unclear how shortfalls in management design or compliance relate to our findings. Analyses such as the one we conducted are crucial in critically evaluating wildlife-management decisions. The results of these analyses can

  8. Strength of noise effects on memory as a function of noise source and age.

    PubMed

    Boman, E; Enmarker, I; Hygge, S

    2005-01-01

    The objectives in this paper were to analyse noise effects on episodic and semantic memory performance in different age groups, and to see whether age interacted with noise in their effects on memory. Data were taken from three separate previous experiments, that were performed with the same design, procedure and dependent measures with participants from four age groups (13-14, 18-20, 35-45 and 55-65 years). Participants were randomly assigned to one of three conditions: (a) meaningful irrelevant speech, (b) road traffic noise, and (c) quiet. The results showed effects of both noise sources on a majority of the dependent measures, both when taken alone and aggregated according to the nature of the material to be memorised. However, the noise effects for episodic memory tasks were stronger than for semantic memory tasks. Further, in the reading comprehension task, cued recall and recognition were more impaired by meaningful irrelevant speech than by road traffic noise. Contrary to predictions, there was no interaction between noise and age group, indicating that the obtained noise effects were not related to the capacity to perform the task. The results from the three experiments taken together throw more light on the relative effects of road traffic noise and meaningful irrelevant speech on memory performance in different age groups.

  9. Noise pollution has limited effects on nocturnal vigilance in peahens.

    PubMed

    Yorzinski, Jessica L; Hermann, Fredrick S

    2016-01-01

    Natural environments are increasingly exposed to high levels of noise pollution. Noise pollution can alter the behavior of animals but we know little about its effects on antipredator behavior. We therefore investigated the impact of noise pollution on vigilance behavior and roost selection in an avian species, peafowl (Pavo cristatus), that inhabits urban environments. Captive peahens were exposed to noise pollution at night and their vigilance levels and roost selections were monitored. The vigilance levels of peahens were unaffected by exposure to noise pollution within trials. Furthermore, the peahens exhibited no preference for roosting farther or closer to noise pollution. Interestingly, predators often avoided the experimental area during nights with noise pollution, which could explain why vigilance rates were higher overall during control compared to noise trials. The results suggest that peahens' perception of risk is not drastically impacted by noise pollution but longer-term studies will be necessary to assess any chronic effects.

  10. Noise pollution has limited effects on nocturnal vigilance in peahens

    PubMed Central

    Hermann, Fredrick S.

    2016-01-01

    Natural environments are increasingly exposed to high levels of noise pollution. Noise pollution can alter the behavior of animals but we know little about its effects on antipredator behavior. We therefore investigated the impact of noise pollution on vigilance behavior and roost selection in an avian species, peafowl (Pavo cristatus), that inhabits urban environments. Captive peahens were exposed to noise pollution at night and their vigilance levels and roost selections were monitored. The vigilance levels of peahens were unaffected by exposure to noise pollution within trials. Furthermore, the peahens exhibited no preference for roosting farther or closer to noise pollution. Interestingly, predators often avoided the experimental area during nights with noise pollution, which could explain why vigilance rates were higher overall during control compared to noise trials. The results suggest that peahens’ perception of risk is not drastically impacted by noise pollution but longer-term studies will be necessary to assess any chronic effects. PMID:27703863

  11. Noise effects on passenger communication in light aircraft

    NASA Technical Reports Server (NTRS)

    Rupf, J. A.

    1977-01-01

    This paper considers the effect of noise on conversation between two persons seated in a close, side-by-side position such as in a small aircraft. Twelve pairs of subjects were required to converse while being exposed to noises of various levels and spectra similar to those currently found in general aviation aircraft. After a period of noise exposure, subjects rated the disruptive effect of the noise on conversation and judged the acceptability of the noise. Subjective estimates of the maximum times for pleasant conversation in the noises were also obtained.

  12. Interspecific comparison of traffic noise effects on dove coo transmission in urban environments

    PubMed Central

    Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen; Lin, Szu-Ying

    2016-01-01

    Most previous studies concerning avian adaptation to anthropogenic noise have focused on songbirds, but few have focused on non-songbirds commonly found in urban environments such as doves. We conducted field playback-recording experiments on the perch-coos of five dove species, including four native Taiwan species (the spotted dove, Spilopelia chinensis, the oriental turtle-dove, Streptopelia orientalis, the red collared-dove, Streptopelia tranquebarica, and the emerald dove, Chalcophaps indica) and one species not native to Taiwan (the zebra dove, Geopelia striata) to evaluate the detection and recognition of dove coos in habitats with differing levels of traffic noise. Our results suggest that traffic noise has selected dominant urban species such as the spotted dove to temporally and spatially adjust cooing to reduce the masking effects of traffic noise and rare urban species such as the emerald dove to avoid areas of high traffic noise. Additionally, although the zebra dove had the highest coo frequency among the study species, its coos showed the highest detection value but not the highest recognition value. We conclude that traffic noise is an important factor in shaping the distribution of rare and dominant dove species in urban environments through its significant effects on coo transmission. PMID:27578359

  13. Interspecific comparison of traffic noise effects on dove coo transmission in urban environments

    NASA Astrophysics Data System (ADS)

    Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen; Lin, Szu-Ying

    2016-08-01

    Most previous studies concerning avian adaptation to anthropogenic noise have focused on songbirds, but few have focused on non-songbirds commonly found in urban environments such as doves. We conducted field playback-recording experiments on the perch-coos of five dove species, including four native Taiwan species (the spotted dove, Spilopelia chinensis, the oriental turtle-dove, Streptopelia orientalis, the red collared-dove, Streptopelia tranquebarica, and the emerald dove, Chalcophaps indica) and one species not native to Taiwan (the zebra dove, Geopelia striata) to evaluate the detection and recognition of dove coos in habitats with differing levels of traffic noise. Our results suggest that traffic noise has selected dominant urban species such as the spotted dove to temporally and spatially adjust cooing to reduce the masking effects of traffic noise and rare urban species such as the emerald dove to avoid areas of high traffic noise. Additionally, although the zebra dove had the highest coo frequency among the study species, its coos showed the highest detection value but not the highest recognition value. We conclude that traffic noise is an important factor in shaping the distribution of rare and dominant dove species in urban environments through its significant effects on coo transmission.

  14. Interspecific comparison of traffic noise effects on dove coo transmission in urban environments.

    PubMed

    Shieh, Bao-Sen; Liang, Shih-Hsiung; Chiu, Yuh-Wen; Lin, Szu-Ying

    2016-08-31

    Most previous studies concerning avian adaptation to anthropogenic noise have focused on songbirds, but few have focused on non-songbirds commonly found in urban environments such as doves. We conducted field playback-recording experiments on the perch-coos of five dove species, including four native Taiwan species (the spotted dove, Spilopelia chinensis, the oriental turtle-dove, Streptopelia orientalis, the red collared-dove, Streptopelia tranquebarica, and the emerald dove, Chalcophaps indica) and one species not native to Taiwan (the zebra dove, Geopelia striata) to evaluate the detection and recognition of dove coos in habitats with differing levels of traffic noise. Our results suggest that traffic noise has selected dominant urban species such as the spotted dove to temporally and spatially adjust cooing to reduce the masking effects of traffic noise and rare urban species such as the emerald dove to avoid areas of high traffic noise. Additionally, although the zebra dove had the highest coo frequency among the study species, its coos showed the highest detection value but not the highest recognition value. We conclude that traffic noise is an important factor in shaping the distribution of rare and dominant dove species in urban environments through its significant effects on coo transmission.

  15. Local noise sensitivity: Insight into the noise effect on chaotic dynamics

    NASA Astrophysics Data System (ADS)

    Sviridova, Nina; Nakamura, Kazuyuki

    2016-12-01

    Noise contamination in experimental data with underlying chaotic dynamics is one of the significant problems limiting the application of many nonlinear time series analysis methods. Although numerous studies have been devoted to the investigation of different aspects of noise—nonlinear dynamics interactions, the effects produced by noise on chaotic dynamics are not fully understood. This study sought to analyze the local effects produced by noise on chaotic dynamics with a smooth attractor. Local Wayland test translation errors were calculated for noise-induced Lorenz and Rössler chaotic models, and for experimental green light photoplethysmogram data. Results demonstrated that under noise induction, local regions on the chaotic attractor with high values of local translation error can be observed. This phenomenon was defined as the local noise sensitivity. It was found that for both models, local noise-sensitive regions were located close to the system's equilibrium points. Additionally, it was found that the reconstructed dynamics represent well the local noise sensitivity of the original dynamics. The concept of local noise sensitivity is expected to contribute to various applied studies, as it reveals regions of chaotic attractors that are sensitive to the presence of noise.

  16. Assessing the Spatial Scale Effect of Anthropogenic Factors on Species Distribution

    PubMed Central

    Mangiacotti, Marco; Scali, Stefano; Sacchi, Roberto; Bassu, Lara; Nulchis, Valeria; Corti, Claudia

    2013-01-01

    Patch context is a way to describe the effect that the surroundings exert on a landscape patch. Despite anthropogenic context alteration may affect species distributions by reducing the accessibility to suitable patches, species distribution modelling have rarely accounted for its effects explicitly. We propose a general framework to statistically detect the occurrence and the extent of such a factor, by combining presence-only data, spatial distribution models and information-theoretic model selection procedures. After having established the spatial resolution of the analysis on the basis of the species characteristics, a measure of anthropogenic alteration that can be quantified at increasing distance from each patch has to be defined. Then the distribution of the species is modelled under competing hypotheses: H0, assumes that the distribution is uninfluenced by the anthropogenic variables; H1, assumes the effect of alteration at the species scale (resolution); and H2, H3 … Hn add the effect of context alteration at increasing radii. Models are compared using the Akaike Information Criterion to establish the best hypothesis, and consequently the occurrence (if any) and the spatial scale of the anthropogenic effect. As a study case we analysed the distribution data of two insular lizards (one endemic and one naturalised) using four alternative hypotheses: no alteration (H0), alteration at the species scale (H1), alteration at two context scales (H2 and H3). H2 and H3 performed better than H0 and H1, highlighting the importance of context alteration. H2 performed better than H3, setting the spatial scale of the context at 1 km. The two species respond differently to context alteration, the introduced lizard being more tolerant than the endemic one. The proposed approach supplies reliably and interpretable results, uses easily available data on species distribution, and allows the assessing of the spatial scale at which human disturbance produces the heaviest

  17. Assessing the Spatial Scale Effect of Anthropogenic Factors on Species Distribution.

    PubMed

    Mangiacotti, Marco; Scali, Stefano; Sacchi, Roberto; Bassu, Lara; Nulchis, Valeria; Corti, Claudia

    2013-01-01

    Patch context is a way to describe the effect that the surroundings exert on a landscape patch. Despite anthropogenic context alteration may affect species distributions by reducing the accessibility to suitable patches, species distribution modelling have rarely accounted for its effects explicitly. We propose a general framework to statistically detect the occurrence and the extent of such a factor, by combining presence-only data, spatial distribution models and information-theoretic model selection procedures. After having established the spatial resolution of the analysis on the basis of the species characteristics, a measure of anthropogenic alteration that can be quantified at increasing distance from each patch has to be defined. Then the distribution of the species is modelled under competing hypotheses: H0, assumes that the distribution is uninfluenced by the anthropogenic variables; H1, assumes the effect of alteration at the species scale (resolution); and H2, H3 … Hn add the effect of context alteration at increasing radii. Models are compared using the Akaike Information Criterion to establish the best hypothesis, and consequently the occurrence (if any) and the spatial scale of the anthropogenic effect. As a study case we analysed the distribution data of two insular lizards (one endemic and one naturalised) using four alternative hypotheses: no alteration (H0), alteration at the species scale (H1), alteration at two context scales (H2 and H3). H2 and H3 performed better than H0 and H1, highlighting the importance of context alteration. H2 performed better than H3, setting the spatial scale of the context at 1 km. The two species respond differently to context alteration, the introduced lizard being more tolerant than the endemic one. The proposed approach supplies reliably and interpretable results, uses easily available data on species distribution, and allows the assessing of the spatial scale at which human disturbance produces the heaviest

  18. Acoustic considerations of flight effects on jet noise suppressor nozzles

    NASA Technical Reports Server (NTRS)

    Vonglahn, U.

    1979-01-01

    The inflight acoustic characteristics of high velocity jet noise suppressor nozzles for supersonic cruise aircraft were reviewed. The inflight effects at the peak noise level were discussed. Both single and inverted velocity profile multistream suppressor nozzles were considered. The importance of static spectral shape on the noise reduction due to inflight effects was stressed.

  19. Extra-auditory effects of noise in laboratory animals: the relationship between noise and sleep.

    PubMed

    Rabat, Arnaud

    2007-01-01

    Noise has both auditory and extra-auditory effects. Some of the most deleterious extra-auditory effects of noise are those leading to sleep disturbances. These disturbances seem to be related to both endogenous (physical parameters) and exogenous (sex, age) factors of noise. Despite correlative relations between noise level and awakenings, the scientific community has not reached consensus regarding a specific action of these factors on the different sleep stages. In animal research, 2 complementary main fields of research exist. One is focused on the positive modulation of sleep by repeated tone stimulation. The other concerns noise-related sleep disturbances. The few studies that have investigated noise-related sleep disturbances suggest the following conclusions. First, sleep disturbances are greater upon exposure to environmental noise, whose frequency spectrum is characterized by high and ultrasonic sounds, than white noise. Second, unpredictability and pattern of noise events are responsible for extractions from both SWS and PS. Third, chronic exposure to noise permanently reduces and fragments sleep. Finally, in chronic noise exposure, an inter-individual variability in SWS deficits is observed and correlated to a psychobiological profile related to an incapability to face stressful situations. Based on results from other research, acute noise-related sleep perturbations could result from an imbalance in the sleep-wake cycle in favor of arousing ascending systems. Chronic noise-related sleep disturbances may arise due to imbalance of the sleep-wake cycle and malfunctioning of the hypothalamo-pituitary-adrenal axis which may both contribute to the development of pathology.

  20. Sources and effects of low-frequency noise.

    PubMed

    Berglund, B; Hassmén, P; Job, R F

    1996-05-01

    The sources of human exposure to low-frequency noise and its effects are reviewed. Low-frequency noise is common as background noise in urban environments, and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and ventilation or air-conditioning units. The effects of low-frequency noise are of particular concern because of its pervasiveness due to numerous sources, efficient propagation, and reduced efficacy of many structures (dwellings, walls, and hearing protection) in attenuating low-frequency noise compared with other noise. Intense low-frequency noise appears to produce clear symptoms including respiratory impairment and aural pain. Although the effects of lower intensities of low-frequency noise are difficult to establish for methodological reasons, evidence suggests that a number of adverse effects of noise in general arise from exposure to low-frequency noise: Loudness judgments and annoyance reactions are sometimes reported to be greater for low-frequency noise than other noises for equal sound-pressure level; annoyance is exacerbated by rattle or vibration induced by low-frequency noise; speech intelligibility may be reduced more by low-frequency noise than other noises except those in the frequency range of speech itself, because of the upward spread of masking. On the other hand, it is also possible that low-frequency noise provides some protection against the effects of simultaneous higher frequency noise on hearing. Research needs and policy decisions, based on what is currently known, are considered.

  1. Effects of Anthropogenic Disturbance and Climate on Patterns of Bat Fly Parasitism

    PubMed Central

    Pilosof, Shai; Dick, Carl W.; Korine, Carmi; Patterson, Bruce D.; Krasnov, Boris R.

    2012-01-01

    Environmental conditions, including anthropogenic disturbance, can significantly alter host and parasite communities. Yet, our current knowledge is based mainly on endoparasites, while ectoparasites remain little studied. We studied the indirect effects of anthropogenic disturbance (human population density) and climate (temperature, precipitation and elevation) on abundance of highly host-specific bat flies in four Neotropical bat species across 43 localities in Venezuela. We formulated a set of 11 a priori hypotheses that included a combination of the two effectors and host species. Statistically, each of these hypotheses was represented by a zero-inflated negative binomial mixture model, allowing us to control for excess zeros in the data. The best model was selected using Akaike's information criteria. Fly abundance was affected by anthropogenic disturbance in Artibeus planirostris, Carollia perspicillata and Pteronotus parnellii, but not Desmodus rotundus. Climate affected fly abundance in all bat species, suggesting mediation of these effects via the host or by direct effects on flies. We conclude that human disturbance may play a role in shaping bat-bat fly interactions. Different processes could determine fly abundance in the different bat species. PMID:22829953

  2. Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global climate model

    PubMed Central

    Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J.; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan H.; Molina, Mario J.

    2014-01-01

    Atmospheric aerosols affect weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the effects of anthropogenic aerosols on the Pacific storm track, using a multiscale global aerosol–climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and preindustrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by −2.5 and +1.3 W m−2, respectively, by emission changes from preindustrial to present day, and an increased cloud top height indicates invigorated midlatitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides, for the first time to the authors’ knowledge, a global perspective of the effects of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multiscale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on a global scale. PMID:24733923

  3. Assessing the effects of anthropogenic aerosols on Pacific storm track using a multiscale global climate model.

    PubMed

    Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan H; Molina, Mario J

    2014-05-13

    Atmospheric aerosols affect weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the effects of anthropogenic aerosols on the Pacific storm track, using a multiscale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and preindustrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by -2.5 and +1.3 W m(-2), respectively, by emission changes from preindustrial to present day, and an increased cloud top height indicates invigorated midlatitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides, for the first time to the authors' knowledge, a global perspective of the effects of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multiscale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on a global scale.

  4. The Effect of Noise on the Precedence Effect

    NASA Astrophysics Data System (ADS)

    Chiang, Yuan-Chuan

    This current study examined the influence of noise on the two processes of the precedence effect: precedence localization and echo threshold in the free-field. In the precedence localization experiment, listeners judged whether the image produced by a lead-lag pair of noise bursts (4 ms delay) presented 3 times was to the right or the left of a comparator. The lead and the lag loudspeakers were fixed at 45 degrees to the right and left of midline, respectively. The comparator consisted of the same noise burst pairs as the test stimulus, and was presented from various angles near the lead loudspeaker. The angle of the comparator loudspeaker producing 50% "left" judgments was used to estimate the perceived location of the stimulus image. This measurement was made for lead-only and lead -lag stimuli. A shift of the estimated image position from the lead-only to the lead-lag condition was used to estimate the perceptual weighting of the lead relative to the lag. Measurements were conducted at equivalent sensation levels in quiet and in noise, and in conditions with noise originating from 7 locations. The weighting, which was quantified using the c metric developed by Shinn-Cunningham et al. (J. Acoust. Soc. Am. 93, 2923-2932 (1993)), strongly favored the lead when the sounds were presented in quiet, and was only slightly reduced when broadband noise was introduced from 180 degrees. This result was in contrast to previous findings of a greatly weakened precedence effect in noise reported by Leakey and Cherry (1957) using a time-intensity trading paradigm. A replication of the former study using the same test paradigm yielded results showing a much stronger effect of noise, suggesting that a strong noise effect exists only when the lag is louder than the lead. In the echo threshold experiment, the same 4-ms noise burst pair was presented once from the previous lead and lag loudspeakers with the delay varying between 2 and 16 ms, in steps of 2. Subjects judged whether

  5. Effects of anthropogenic surfactants on the conversion of marine dissolved organic carbon and microgels.

    PubMed

    Shiu, Ruei-Feng; Lee, Chon-Lin

    2017-04-15

    The possible impact of three types of anthropogenic surfactants on the ability of marine dissolved organic carbon (DOC) to form self-assembled microgels was evaluated. The behavior of existing native microgels was also examined in the presence of surfactants. These results reveal that the release of surfactants even at low concentrations into the aquatic environment could effectively hinder the self-assembly of DOC polymers. The extent of the size reduction had the following order: anionic, cationic, and non-ionic. Furthermore, charged surfactants can disrupt existing native microgels, converting large assemblies into smaller particles. One possible mechanisms is that surfactants are able to enhance the stability of DOC polymers and disrupt aggregates due to their surface charges and protein-denaturing activities. These findings suggest that the ecological system is altered by anthropogenic surfactants, and provide useful information for ecological assessments of different types of surfactants and raise warnings about surfactant applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Effects of Anthropogenic Activity on the Hydrogeochemistry of Nakdong River, Korea

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Ha, S.

    2016-12-01

    The hydrogeochemistry of the river water is affected by many different factors including anthropogenic activity and rock weathering. With urbanization, the anthropogenic effects play more important roles in the hydrogeochemisty of river waters. The Nakdong River is the second largest but the longest river in Korea. The drainage area of the Nakdong basin is about 23,384 km2. This river flows through two cities, Daegu and Busan, which are the third and second largest ones in Korea, and therefore, the anthopogenic effects from these cities as well as those from the weathering of the bedrocks on the geochemcial compositions of the river are expected to be significant. Considering the seasonal effects and precipitaion rate, the water samples of river and tributaries were collected three times in Novermber, May, and July, respectively. The hydrogeochemical facies from Piper diagram shows that it changes from Ca-SO4/Ca-HCO3 type to Na-SO4 one from upstream to downstream, indicating that the anthropogenic effects from large cities which are located in downstream region become more significant. However, considering the geochemical compositions of cations (Ca > Na > Mg > K) and anions (HCO3 > SO4 > Cl > NO3), the major contributions to the hydrogeochemistry of this river are from the weathering of the bedrocks. The geology of the basin area is mainly composed of granitic and gneissic rocks in upstream region and sedimentary and granitic rocks in downstream one. For the major cations, Na shows the highest concentrations near Daegu in which large industrial complex is also located, stronly indicating that the anthopogenic effects are quite significant in this area. The high concentrations of Na are also accompanied by the high concentrations of SO4, which is consiered as one of the major anions from pollutant source. The concentrations of those two elements decrease downstream and do not increase near Busan, which is located most downstream. Phospahte were also detected in

  7. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability.

    PubMed

    Ghan, Steven; Wang, Minghuai; Zhang, Shipeng; Ferrachat, Sylvaine; Gettelman, Andrew; Griesfeller, Jan; Kipling, Zak; Lohmann, Ulrike; Morrison, Hugh; Neubauer, David; Partridge, Daniel G; Stier, Philip; Takemura, Toshihiko; Wang, Hailong; Zhang, Kai

    2016-05-24

    A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing.

  8. Anthropogenic natal environmental effects on life histories in a wild bird population.

    PubMed

    Cartwright, Samantha J; Nicoll, Malcolm A C; Jones, Carl G; Tatayah, Vikash; Norris, Ken

    2014-03-03

    Recent work suggests that the environment experienced in early life can alter life histories in wild populations, but our understanding of the processes involved remains limited. Since anthropogenic environmental change is currently having a major impact on wild populations, this raises the possibility that life histories may be influenced by human activities that alter environmental conditions in early life. Whether this is the case and the processes involved remain unexplored in wild populations. Using 23 years of longitudinal data on the Mauritius kestrel (Falco punctatus), a tropical forest specialist, we found that females born in territories affected by anthropogenic habitat change shifted investment in reproduction to earlier in life at the expense of late life performance. They also had lower survival rates as young adults. This shift in life history strategy appears to be adaptive, because fitness was comparable to that of other females experiencing less anthropogenic modification in their natal environment. Our results suggest that human activities can leave a legacy on wild birds through natal environmental effects. Whether these legacies have a detrimental effect on populations will depend on life history responses and the extent to which these reduce individual fitness.

  9. Effects of anthropogenic particles on the chemical and geophysical properties of urban soils, Detroit, Michigan

    NASA Astrophysics Data System (ADS)

    Orlicki, Katharine M.

    There is a great need in many cities for a better quality of urban soil maps. This is due to the increasing interest in repurposing vacant land for urban redevelopment, agriculture, and green infrastructure. Mapping vacant urban land in Detroit can be very difficult because anthropogenic soils were often highly variable and frequently contained demolition debris (such as brick), making it difficult to use a hand auger. This study was undertaken in Detroit, MI to create a more efficient way to map urban soils based on their geophysical and chemical properties. This will make the mapping process faster, less labor intensive, and therefore more cost effective. Optical and chemical criteria for the identification and classification of microartifacts (MAs) were made from a set of reference artifacts of a known origin. These MAs were then observed and tested in urban topsoil samples from sites in Detroit, Michigan that represent three different land use types (residential demolition, fly ash-impacted, and industrial). Optical analyses, SEM, EDAX, and XRD showed that reference MAs may be classified into five basic compositional types (carbonaceous, calcareous, siliceous, ferruginous and miscellaneous). Reference MAs were generally distinguishable using optical microscopy by color, luster, fracture and microtexture. MAs that were more difficult to classify were further differentiable when using SEM, EDAX, and XRD. MAs were found in all of the anthropogenic soils studied, but were highly variable. All three study sites had concentrations coal-related wastes were the most common types of MAs observed and often included coal, ash (microspheres, microagglomerate), cinders, and burnt shale. MAs derived from waste building materials such as brick, mortar, and glass, were typically found on residential demolition sites. Manufacturing waste MAs, which included iron-making slag and coked coal were commonly observed on industrial sites. Fly ash-impacted sites were composed of only

  10. Noise effects on conflicting interest quantum games with incomplete information

    NASA Astrophysics Data System (ADS)

    Situ, Haozhen; Huang, Zhiming; Zhang, Cai

    2016-09-01

    Noise effects can be harmful to quantum information systems. In the present paper, we study noise effects in the context of quantum games with incomplete information, which have more complicated structure than quantum games with complete information. The effects of several paradigmatic noises on three newly proposed conflicting interest quantum games with incomplete information are studied using numerical optimization method. Intuitively noises will bring down the payoffs. However, we find that in some situations the outcome of the games under the influence of noise effects are counter-intuitive. Sometimes stronger noise may lead to higher payoffs. Some properties of the game, like quantum advantage, fairness and equilibrium, are invulnerable to some kinds of noises.

  11. Effect of Microscopic Noise on Front Propagation

    NASA Astrophysics Data System (ADS)

    Brunet, Éric; Derrida, Bernard

    2001-04-01

    We study the effect of the noise due to microscopic fluctuations on the position of a one dimensional front propagating from a stable to an unstable region in the "linearly marginal stability case." By simulating a very simple system for which the effective number N of particles can be as large as N=10150, we measure the N dependence of the diffusion constant DN of the front and the shift of its velocity vN. Our results indicate that DN˜(log N)-3. They also confirm our recent claim that the shift of velocity scales like vmin-vN≃K(log N)-2 and indicate that the numerical value of K is very close to the analytical expression Kapprox obtained in our previous work using a simple cut-off approximation.

  12. The Effect of Noise and Display Orientation on Cognitive Performance.

    DTIC Science & Technology

    1983-09-01

    letters among which digits were interspersed. The task was to add up the series of digits . When a series of such sums had been completed, the noise...different abilities (reaction time, rate control, and time sharing). The effect of random 85 dB white noise on performance depended on the type of task and...continuous 95 dB white noise, 95 dB patterned noise, and random intermittent noise. An analysis of the above conflict, that is, the facili- tative effect

  13. Acoustic considerations of flight effects on jet noise suppressor nozzles

    NASA Technical Reports Server (NTRS)

    Von Glahn, U.

    1980-01-01

    Insight into the inflight acoustic characteristics of high-velocity jet noise suppressor nozzles for supersonic cruise aircraft (SCA) is provided. Although the suppression of jet noise over the entire range of directivity angles is of interest, the suppression of the peak noise level in the rear quadrant is frequently of the most interest. Consequently, the paper is directed primarily to the inflight effects at the peak noise level. Both single and inverted-velocity-profile multistream suppressor nozzles are considered. The importance of static spectral shape on the noise reduction due to inflight effects is stressed.

  14. Effect of tactile vibration on annoyance to synthesized propfan noise

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.

    1981-01-01

    Design information that maximizes passenger comfort for propfan aircraft is presented. Predicted noise and vibration environments and the resultant passenger acceptability were studied. The effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions was analyzed. Passenger reactions to a wide range of noise with and without tactile vibration was studied. The passenger ride quality simulator was employed using subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80-100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50-200 Hz), two harmonic rolloffs, and three tone/noise ratios. It is indicated that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.

  15. Effect of Poisson noise on adiabatic quantum control

    NASA Astrophysics Data System (ADS)

    Kiely, A.; Muga, J. G.; Ruschhaupt, A.

    2017-01-01

    We present a detailed derivation of the master equation describing a general time-dependent quantum system with classical Poisson white noise and outline its various properties. We discuss the limiting cases of Poisson white noise and provide approximations for the different noise strength regimes. We show that using the eigenstates of the noise superoperator as a basis can be a useful way of expressing the master equation. Using this, we simulate various settings to illustrate different effects of Poisson noise. In particular, we show a dip in the fidelity as a function of noise strength where high fidelity can occur in the strong-noise regime for some cases. We also investigate recent claims [J. Jing et al., Phys. Rev. A 89, 032110 (2014), 10.1103/PhysRevA.89.032110] that this type of noise may improve rather than destroy adiabaticity.

  16. Assessing the Effects of Anthropogenic Aerosols on Pacific Storm Track Using a Multiscale Global Climate Model

    SciTech Connect

    Wang, Yuan; Wang, Minghuai; Zhang, Renyi; Ghan, Steven J.; Lin, Yun; Hu, Jiaxi; Pan, Bowen; Levy, Misti; Jiang, Jonathan; Molina, Mario J.

    2014-05-13

    Atmospheric aerosols impact weather and global general circulation by modifying cloud and precipitation processes, but the magnitude of cloud adjustment by aerosols remains poorly quantified and represents the largest uncertainty in estimated forcing of climate change. Here we assess the impacts of anthropogenic aerosols on the Pacific storm track using a multi-scale global aerosol-climate model (GCM). Simulations of two aerosol scenarios corresponding to the present day and pre-industrial conditions reveal long-range transport of anthropogenic aerosols across the north Pacific and large resulting changes in the aerosol optical depth, cloud droplet number concentration, and cloud and ice water paths. Shortwave and longwave cloud radiative forcing at the top of atmosphere are changed by - 2.5 and + 1.3 W m-2, respectively, by emission changes from pre-industrial to present day, and an increased cloud-top height indicates invigorated mid-latitude cyclones. The overall increased precipitation and poleward heat transport reflect intensification of the Pacific storm track by anthropogenic aerosols. Hence, this work provides for the first time a global perspective of the impacts of Asian pollution outflows from GCMs. Furthermore, our results suggest that the multi-scale modeling framework is essential in producing the aerosol invigoration effect of deep convective clouds on the global scale.

  17. Anthropogenic Halo Disturbances Alter Landscape and Plant Richness: A Ripple Effect

    PubMed Central

    Liu, Bingliang; Su, Jinbao; Chen, Jianwei; Cui, Guofa; Ma, Jianzhang

    2013-01-01

    Although anthropogenic landscape fragmentation is often considered as the primary threat to biodiversity, other factors such as immediate human disturbances may also simultaneously threaten species persistence in various ways. In this paper, we introduce a conceptual framework applied to recreation landscapes (RLs), with an aim to provide insight into the composite influences of landscape alteration accompanying immediate human disturbances on plant richness dynamics. These impacts largely occur at patch-edges. They can not only alter patch-edge structure and environment, but also permeate into surrounding natural matrices/patches affecting species persistence–here we term these “Halo disturbance effects” (HDEs). We categorized species into groups based on seed or pollen dispersal mode (animal- vs. wind-dispersed) as they can be associated with species richness dynamics. We evaluated the richness of the two groups and total species in our experimental landscapes by considering the distance from patch-edge, the size of RLs and the intensity of human use over a six-year period. Our results show that animal-dispersed species decreased considerably, whereas wind-dispersed species increased while their richness presented diverse dynamics at different distances from patch-edges. Our findings clearly demonstrate that anthropogenic HDEs produce ripple effects on plant, providing an experimental interpretation for the diverse responses of species to anthropogenic disturbances. This study highlights the importance of incorporating these composite threats into conservation and management strategies. PMID:23424648

  18. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes)

    PubMed Central

    Carlitz, Esther H. D.; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C.; van Schaik, Carel P.

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

  19. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes).

    PubMed

    Carlitz, Esther H D; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C; van Schaik, Carel P

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species.

  20. National policy on the effects of underwater noise on marine mammals and turtles

    NASA Astrophysics Data System (ADS)

    Gentry, Roger L.

    2002-05-01

    Marine anthropogenic noise is increasing at an unknown rate yet its effects on mammals and turtles are poorly documented. Such information is central to noise standards for marine animals required by two federal laws (MMPA and ESA). Good policy on underwater noise would set standards that are neither too liberal (thereby threatening the well being of marine animals), nor too conservative (thereby unnecessarily impairing essential human activities at sea). This balance must be found using existing data; standards cannot await new research. Policy must also lay out rules governing the introduction of novel underwater sound sources whose effects on animals are unknown. Should policy forbid such introductions until all possible consequences are known, or does a safe, incremental method of introduction exist? Should exceptions be made for novel sources associated with national defense? Policy must cope with sound sources that are outside the reach of U.S. federal regulations, such as international shipping. Finally, policy must frame the questions about underwater noise in a way that research can answer. Specifically, how much noise exists, how fast is it growing, where is it, and what consequences does it have for animals and their ecosystems?

  1. 78 FR 78822 - Draft Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammals-Acoustic...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-27

    ... (NOAA), Commerce. ACTION: Notice; request for comments. SUMMARY: The National Marine Fisheries Service... Oceanic and Atmospheric Administration (NOAA)), announces the availability of draft guidance for assessing the effects of anthropogenic sound on marine mammal species under NOAA's jurisdiction. The...

  2. High speed flight effects on noise propagation

    NASA Astrophysics Data System (ADS)

    Burrin, R. H.; Ahuja, K. K.; Salikuddin, M.

    1987-01-01

    An experimental study to investigate the effects of source motion on sound propagation at high Mach numbers was devised to determine, in particular, if the large amplifications in the forward arc to high speeds, predicted by the 'convective amplification' factors normally used for low speeds, are realistic. An acoustic point source and a microphone, both immersed in flows up to a Mach number of 0.8, were used to obtain the convective amplification factors for comparison with predictions. The results confirmed the existence of high levels of noise propagating ahead of an aircraft flying at high speed. The commonly adopted prediction formula, namely (1 - M sub 0 cos theta sub E) exp -4, was categorically confirmed by the data for frequencies up to 5 kHz and Mach numbers of 0.2 to 0.8. At higher frequencies, the predictions are followed up to emission angles of 120 deg, but then deviate downward towards the direction of flight.

  3. Meta-analysis of anthropogenic habitat disturbance effects on animal-mediated seed dispersal.

    PubMed

    Fontúrbel, Francisco E; Candia, Alina B; Malebrán, Javiera; Salazar, Daniela A; González-Browne, Catalina; Medel, Rodrigo

    2015-11-01

    Anthropogenic habitat disturbance is a strong biodiversity change driver that compromises not only the species persistence but also the ecological interactions in which they are involved. Even though seed dispersal is a key interaction involved in the recruitment of many tree species and in consequence critical for biodiversity maintenance, studies assessing the effect of different anthropogenic disturbance drivers on this interaction have not been performed under a meta-analytical framework. We assessed the way habitat fragmentation and degradation processes affect species diversity (abundance and species richness) and interaction rates (i.e., fruit removal and visitation rates) of different groups of seed-disperser species at a global scale. We obtained 163 case studies from 37 articles. Results indicate that habitat degradation had a negative effect on seed-disperser animal diversity, whereas habitat fragmentation had a negative effect on interaction rates. Birds and insects were more sensitive in terms of their diversity, whereas mammals showed a negative effect on interaction rates. Regarding habitat, both fragmentation and degradation had a negative effect on seed-disperser animal diversity only in temperate habitats, and negative effects on interaction rates in tropical and temperate habitats. Our results indicate that the impact of human disturbance on seed-disperser species and interactions is not homogeneous. On the contrary, the magnitude of effects seems to be dependent on the type of disturbance, taxonomic group under assessment, and geographical region where the human impact occurs. © 2015 John Wiley & Sons Ltd.

  4. Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar.

    PubMed

    Farris, Zach J; Golden, Christopher D; Karpanty, Sarah; Murphy, Asia; Stauffer, Dean; Ratelolahy, Felix; Andrianjakarivelo, Vonjy; Holmes, Christopher M; Kelly, Marcella J

    2015-01-01

    The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting) affect carnivore occupancy across Madagascar's largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species) and domestic dogs (Canis familiaris) had higher occupancy than half of the native carnivore species across Madagascar's largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana) occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica). Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (mean=90 individuals consumed/year), the ring-tailed vontsira (Galidia elegans) (mean=58 consumed/year), and the fosa (Cryptoprocta ferox) (mean=31 consumed/year). Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are highest. These various

  5. Auditory and non-auditory effects of noise on health.

    PubMed

    Basner, Mathias; Babisch, Wolfgang; Davis, Adrian; Brink, Mark; Clark, Charlotte; Janssen, Sabine; Stansfeld, Stephen

    2014-04-12

    Noise is pervasive in everyday life and can cause both auditory and non-auditory health effects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mechanisms involved in noise-induced hair-cell and nerve damage has substantially increased, and preventive and therapeutic drugs will probably become available within 10 years. Evidence of the non-auditory effects of environmental noise exposure on public health is growing. Observational and experimental studies have shown that noise exposure leads to annoyance, disturbs sleep and causes daytime sleepiness, affects patient outcomes and staff performance in hospitals, increases the occurrence of hypertension and cardiovascular disease, and impairs cognitive performance in schoolchildren. In this Review, we stress the importance of adequate noise prevention and mitigation strategies for public health.

  6. Auditory and non-auditory effects of noise on health

    PubMed Central

    Basner, Mathias; Babisch, Wolfgang; Davis, Adrian; Brink, Mark; Clark, Charlotte; Janssen, Sabine; Stansfeld, Stephen

    2014-01-01

    Noise is pervasive in everyday life and can cause both auditory and non-auditory health effects. Noise-induced hearing loss remains highly prevalent in occupational settings, and is increasingly caused by social noise exposure (eg, through personal music players). Our understanding of molecular mechanisms involved in noise-induced hair-cell and nerve damage has substantially increased, and preventive and therapeutic drugs will probably become available within 10 years. Evidence of the non-auditory effects of environmental noise exposure on public health is growing. Observational and experimental studies have shown that noise exposure leads to annoyance, disturbs sleep and causes daytime sleepiness, affects patient outcomes and staff performance in hospitals, increases the occurrence of hypertension and cardiovascular disease, and impairs cognitive performance in schoolchildren. In this Review, we stress the importance of adequate noise prevention and mitigation strategies for public health. PMID:24183105

  7. Colored noise effects on batch attitude accuracy estimates

    NASA Technical Reports Server (NTRS)

    Bilanow, Stephen

    1991-01-01

    The effects of colored noise on the accuracy of batch least squares parameter estimates with applications to attitude determination cases are investigated. The standard approaches used for estimating the accuracy of a computed attitude commonly assume uncorrelated (white) measurement noise, while in actual flight experience measurement noise often contains significant time correlations and thus is colored. For example, horizon scanner measurements from low Earth orbit were observed to show correlations over many minutes in response to large scale atmospheric phenomena. A general approach to the analysis of the effects of colored noise is investigated, and interpretation of the resulting equations provides insight into the effects of any particular noise color and the worst case noise coloring for any particular parameter estimate. It is shown that for certain cases, the effects of relatively short term correlations can be accommodated by a simple correction factor. The errors in the predicted accuracy assuming white noise and the reduced accuracy due to the suboptimal nature of estimators that do not take into account the noise color characteristics are discussed. The appearance of a variety of sample noise color characteristics are demonstrated through simulation, and their effects are discussed for sample estimation cases. Based on the analysis, options for dealing with the effects of colored noise are discussed.

  8. Does noise affect learning? A short review on noise effects on cognitive performance in children

    PubMed Central

    Klatte, Maria; Bergström, Kirstin; Lachmann, Thomas

    2013-01-01

    The present paper provides an overview of research concerning both acute and chronic effects of exposure to noise on children's cognitive performance. Experimental studies addressing the impact of acute exposure showed negative effects on speech perception and listening comprehension. These effects are more pronounced in children as compared to adults. Children with language or attention disorders and second-language learners are still more impaired than age-matched controls. Noise-induced disruption was also found for non-auditory tasks, i.e., serial recall of visually presented lists and reading. The impact of chronic exposure to noise was examined in quasi-experimental studies. Indoor noise and reverberation in classroom settings were found to be associated with poorer performance of the children in verbal tasks. Regarding chronic exposure to aircraft noise, studies consistently found that high exposure is associated with lower reading performance. Even though the reported effects are usually small in magnitude, and confounding variables were not always sufficiently controlled, policy makers responsible for noise abatement should be aware of the potential impact of environmental noise on children's development. PMID:24009598

  9. Remote analysis of anthropogenic effect on boreal forests using nonlinear multidimensional models

    NASA Astrophysics Data System (ADS)

    Shchemel, Anton; Ivanova, Yuliya; Larko, Alexander

    Nowadays anthropogenic stress of mining and refining oil and gas is becoming significant prob-lem in Eastern Siberia. The task of revealing effect of that industry is not trivial because of complicated access to the sites of mining. Due to that, severe problem of supplying detection of oil and gas complex effect on forest ecosystems arises. That estimation should allow revealing the sites of any negative changes in forest communities in proper time. The intellectual system of analyzing remote sensing data of different resolution and different spectral characteristics with sophisticated nonlinear models is dedicated to solve the problem. The work considers re-mote detection and estimation of forest degradation using analysis of free remote sensing data without total field observations of oil and gas mining territory. To analyze a state of vegetation the following remote sensing data were used as input parameters for our models: albedo, surface temperature and data of about thirty spectral bands in visible and infrared region. The data of MODIS satellite from the year 2000 was used. Chosen data allowed producing complex estima-tion of parameters linked with the quality (set of species, physiological state) and the quantity of vegetation. To verify obtained estimation each index was calculated for a territory in which oil and gas mining is provided along with the same calculations for a sample "clear" territory. Monthly data for vegetation period and annual mean values were analyzed. The work revealed some trends of annual data probably linked with intensification of anthropogenic effect on the ecosystems. The models we managed to build are easy to apply for using by fair personnel of emergency control and oversight institutions. It was found to be helpful to use exactly the full set of values obtained from the satellite for multilateral estimation of anthropogenic effect on forest ecosystems of objects of the oil mining industry for producing generalized estimation

  10. Toxic cascades: multiple anthropogenic stressors have complex and unanticipated interactive effects on temperate reefs.

    PubMed

    Shears, Nick T; Ross, Philip M

    2010-09-01

    In a changing environment multiple anthropogenic stressors can have novel and non-additive effects on interacting species. We investigated the interactive effects of fishing and harmful algal blooms on the predator-sea urchin-macroalgae trophic cascade. Fishing of urchin predators had indirect negative effects on macroalgae, whereas blooms of epi-benthic dinoflagellates (Ostreopsis siamensis) were found to have strong negative effects on urchins and indirect positive effects on macroalgae. Based on these opposing effects, blooms were expected to counteract the cascading effects of fishing. However, a large bloom of Ostreopsis led to greater divergence in macroalgae abundance between reserve and fished sites, as urchins declined at reserve sites but remained stable at fished sites. This resulted from enhanced predation rates on bloom-affected urchins at reserve sites rather than direct lethal effects of Ostreopsis on urchins. We argue that interacting stressors can facilitate or attenuate trophic cascades depending on stressor intensity and complex non-lethal interactions.

  11. Evaluating the effects of anthropogenic stressors on source-sink dynamics in pond-breeding amphibians.

    PubMed

    Willson, John D; Hopkins, William A

    2013-06-01

    Although interwetland dispersal is thought to play an important role in regional persistence of pond-breeding amphibians, few researchers have modeled amphibian metapopulation or source-sink dynamics. Results of recent modeling studies suggest anthropogenic stressors, such as pollution, can negatively affect density and population viability of amphibians breeding in isolated wetlands. Presumably population declines also result in reduced dispersal to surrounding (often uncontaminated) habitats, potentially affecting dynamics of nearby populations. We used our data on the effects of mercury (Hg) on the American toad ( Bufo americanus) as a case study in modeling the effects of anthropogenic stressors on landscape-scale amphibian dynamics. We created a structured metapopulation model to investigate regional dynamics of American toads and to evaluate the degree to which detrimental effects of Hg contamination on individual populations can disrupt interpopulation dynamics. Dispersal from typical American toad populations supported nearby populations that would otherwise have been extirpated over long time scales. Through support of such sink populations, dispersal between wetland-associated subpopulations substantially increased overall productivity of wetland networks, but this effect declined with increasing interwetland distance and decreasing wetland size. Contamination with Hg substantially reduced productivity of wetland-associated subpopulations and impaired the ability of populations to support nearby sinks within relevant spatial scales. Our results add to the understanding of regional dynamics of pond-breeding amphibians, the wide-reaching negative effects of environmental contaminants, and the potential for restoration or remediation of degraded habitats.

  12. Effectiveness of combined aircraft engine noise suppressors

    NASA Astrophysics Data System (ADS)

    Khaletskiy, Yu. D.

    2012-07-01

    We consider the design features of fan noise suppressors in application to air intakes and the bypass duct of a turbofan engine. A combined liner is developed that has increased acoustic efficiency in comparison to conventional honeycomb liner. We demonstrate the important role of the area of the sound-absorbing liner between fan Rotor and Stator ensuring significant noise reduction.

  13. Effects of noise correlations on information encoding and decoding.

    PubMed

    Averbeck, Bruno B; Lee, Daeyeol

    2006-06-01

    Response variability is often correlated across populations of neurons, and these noise correlations may play a role in information coding. In previous studies, this possibility has been examined from the encoding and decoding perspectives. Here we used d prime and related information measures to examine how studies of noise correlations from these two perspectives are related. We found that for a pair of neurons, the effect of noise correlations on information decoding can be zero when the effect of noise correlations on the information encoded obtains its largest positive or negative values. Furthermore, there can be no effect of noise correlations on the information encoded when it has an effect on information decoding. We also measured the effect of noise correlations on information encoding and decoding in simultaneously recorded neurons in the supplementary motor area to see how well d prime accounted for the information actually present in the neural responses and to see how noise correlations affected encoding and decoding in real data. These analyses showed that d prime provides an accurate measure of information encoding and decoding in our population of neurons. We also found that the effect of noise correlations on information encoding was somewhat larger than the effect of noise correlations on information decoding, but both were relatively small. Finally, as predicted theoretically, the effects of correlations were slightly greater for larger ensembles (3-8 neurons) than for pairs of neurons.

  14. Nonauditory-system response to noise and effects on health

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Continued exposure to noise in real life can be a source of physiological stress possibly capable of causing health disorders beyond that of direct damage to the auditory receptor system. Some theorists hold that some of these effects occur because of innate, reflexive responses to noise that cannot be prevented or, when suppressed, that require some effort that may itself become somewhat debilitting in time. An alternative theory is that the truly nonhabituating reflexive responses to noise are not sufficient in character to cause any ill health, and that those responses to noise that are or could be significant in this regard are not directly the result of exposure to noise but are responses to the emotional meanings conveyed by the sounds. Obviously, the degree to which noise can lead to harm to nonauditory physiological systems of the body are questions of utmost importance for the assessment of the need for noise control.

  15. Social and demographic effects of anthropogenic mortality: a test of the compensatory mortality hypothesis in the red wolf.

    PubMed

    Sparkman, Amanda M; Waits, Lisette P; Murray, Dennis L

    2011-01-01

    Whether anthropogenic mortality is additive or compensatory to natural mortality in animal populations has long been a question of theoretical and practical importance. Theoretically, under density-dependent conditions populations compensate for anthropogenic mortality through decreases in natural mortality and/or increases in productivity, but recent studies of large carnivores suggest that anthropogenic mortality can be fully additive to natural mortality and thereby constrain annual survival and population growth rate. Nevertheless, mechanisms underlying either compensatory or additive effects continue to be poorly understood. Using long-term data on a reintroduced population of the red wolf, we tested for evidence of additive vs. compensatory effects of anthropogenic mortality on annual survival and population growth rates, and the preservation and reproductive success of breeding pairs. We found that anthropogenic mortality had a strong additive effect on annual survival and population growth rate at low population density, though there was evidence for compensation in population growth at high density. When involving the death of a breeder, anthropogenic mortality was also additive to natural rates of breeding pair dissolution, resulting in a net decrease in the annual preservation of existing breeding pairs. However, though the disbanding of a pack following death of a breeder resulted in fewer recruits per litter relative to stable packs, there was no relationship between natural rates of pair dissolution and population growth rate at either high or low density. Thus we propose that short-term additive effects of anthropogenic mortality on population growth in the red wolf population at low density were primarily a result of direct mortality of adults rather than indirect socially-mediated effects resulting in reduced recruitment. Finally, we also demonstrate that per capita recruitment and the proportion of adults that became reproductive declined steeply

  16. Contrasting effects of anthropogenic and natural acidity in streams: a meta-analysis.

    PubMed

    Petrin, Zlatko; Englund, Göran; Malmqvist, Björn

    2008-05-22

    Large-scale human activities including the extensive combustion of fossil fuels have caused acidification of freshwater systems on a continental scale, resulting in reduced species diversity and, in some instances, impaired ecological functioning. In regions where acidity is natural, however, species diversity and functioning seem to be less affected. This contrasting response is likely to have more than one explanation including the possibility of adaptation in organisms exposed to natural acidity over evolutionary time scales and differential toxicity due to dissimilarities in water chemistry other than pH. However, empirical evidence supporting these hypotheses is equivocal. Partly, this is because previous research has mainly been conducted at relatively small geographical scales, and information on ecological functioning in this context is generally scarce. Our goal was to test whether anthropogenic acidity has stronger negative effects on species diversity and ecological functioning than natural acidity. Using a meta-analytic approach based on 60 datasets, we show that macroinvertebrate species richness and the decomposition of leaf litter -- an important process in small streams -- tend to decrease with increasing acidity across regions and across both the acidity categories. Macroinvertebrate species richness, however, declines three times more rapidly with increasing acidity where it is anthropogenic than where it is natural, in agreement with the adaptation hypothesis and the hypothesis of differences in water chemistry. By contrast, the loss in ecological functioning differs little between the categories, probably because increases in the biomass of taxa remaining at low pH compensate for losses in functionality that would otherwise accompany losses of taxa from acidic systems. This example from freshwater acidification illustrates how natural and anthropogenic stressors can differ markedly in their effects on species diversity and one aspect of

  17. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability

    PubMed Central

    Ghan, Steven; Wang, Minghuai; Zhang, Shipeng; Ferrachat, Sylvaine; Gettelman, Andrew; Griesfeller, Jan; Kipling, Zak; Lohmann, Ulrike; Morrison, Hugh; Neubauer, David; Partridge, Daniel G.; Stier, Philip; Takemura, Toshihiko; Wang, Hailong; Zhang, Kai

    2016-01-01

    A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing. PMID:26921324

  18. The effects of noise on key workplace skills.

    PubMed

    Molesworth, Brett R C; Burgess, Marion; Zhou, Annie

    2015-10-01

    This study explored the effect on memory and psychomotor performance of wideband noise (simulated in-cabin aircraft noise) at 75 dBA, which is similar to that experienced during the cruise phase of a commercial flight. The results from the tests were compared to the effects of a widely known and common metric on the same skills, namely, blood alcohol concentration (BAC). All 32 participants, half non-native English speakers, completed three different tests (recognition memory, working memory, and reaction time) presented in counterbalanced order, either in the presence of noise, with or without noise attenuation headphones, and without noise but with a BAC of 0.05 or 0.10. Simulated aircraft noise was found to affect recognition memory but not working memory or reaction time. These effects were more pronounced for non-native speakers and reflected performance similar to that for BAC of 0.05 or 0.10.

  19. Jets over Labrador and Quebec: noise effects on human health.

    PubMed Central

    Rosenberg, J

    1991-01-01

    OBJECTIVE: To determine whether the noise from low-level flights over Labrador and Quebec is harmful to human health. DATA SOURCE AND SELECTION: Search of MEDLINE for articles on the effect of noise, particularly impulse noise associated with low-level flights, and a search of the references from identified articles. DATA SYNTHESIS: The noise levels from low-level flights could affect hearing acuity. However, the more important consequences appear to be stress-mediated physiologic effects, especially cardiovascular ones, and psychologic distress, particularly in children. Subjective perception of control over the noise has been found to mitigate some physiologic effects. CONCLUSION: There is sufficient evidence to show that the noise from low-level flights is harmful to human health. PMID:2007238

  20. [Effect of noise on circulatory disorders].

    PubMed

    Reinharez, D

    1989-01-01

    The author reports a dramatic case of severe functional and trophic disorders of the lower limbs which proved to be entirely caused by noise. This case led him to study noise and its repercussions on the vascular system: physical characteristics, methods of measurement, epidemiology of this environmental nuisance, general and vascular diseases produced by the traumatic-vibration syndrome, and study of its mechanism of action. He concludes by calling for interdisciplinary action to combine fundamental research, screening and prevention of the disorders caused by noise.

  1. Durations required to distinguish noise and tone: Effects of noise bandwidth and frequency.

    PubMed

    Taghipour, Armin; Moore, Brian C J; Edler, Bernd

    2016-05-01

    Perceptual audio coders exploit the masking properties of the human auditory system to reduce the bit rate in audio recording and transmission systems; it is intended that the quantization noise is just masked by the audio signal. The effectiveness of the audio signal as a masker depends on whether it is tone-like or noise-like. The determination of this, both physically and perceptually, depends on the duration of the stimuli. To gather information that might improve the efficiency of perceptual coders, the duration required to distinguish between a narrowband noise and a tone was measured as a function of center frequency and noise bandwidth. In experiment 1, duration thresholds were measured for isolated noise and tone bursts. In experiment 2, duration thresholds were measured for tone and noise segments embedded within longer tone pulses. In both experiments, center frequencies were 345, 754, 1456, and 2658 Hz and bandwidths were 0.25, 0.5, and 1 times the equivalent rectangular bandwidth of the auditory filter at each center frequency. The duration thresholds decreased with increasing bandwidth and with increasing center frequency up to 1456 Hz. It is argued that the duration thresholds depended mainly on the detection of amplitude fluctuations in the noise bursts.

  2. Alien plant invasion in mixed-grass prairie: Effects of vegetation type and anthropogenic disturbance

    USGS Publications Warehouse

    Larson, D.L.; Anderson, P.J.; Newton, W.

    2001-01-01

    The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of

  3. Effects of aircraft cabin noise on passenger comfort.

    PubMed

    Pennig, Sibylle; Quehl, Julia; Rolny, Vinzent

    2012-01-01

    The effects of cabin noise on subjective comfort assessments were systematically investigated in order to reveal optimisation potentials for an improved passenger noise acceptance. Two aircraft simulation studies were conducted. An acoustic laboratory test facility provided with loudspeaker systems for realistic sound presentations and an aircraft cabin simulator (Dornier Do 728) with a high degree of ecological validity were used. Subjects were exposed to nine different noise patterns (three noise levels ranging from 66 to 78 dB(A) combined with three different frequency spectra). Regression analysis demonstrated a significant increase of passengers' acceptance with lower noise levels and significant effects of different frequency spectra determined by seat position in the aircraft cabin (front, middle, rear). Acoustic cabin design should therefore consider measures beyond noise level reduction altering noise characteristics to improve passengers' comfort and well-being in the aircraft cabin. To improve passenger comfort in the aircraft with respect to cabin noise, passengers' reactions to specific noise conditions were systematically investigated. Two laboratory studies showed significant dose-response relationships between sound pressure level and subjective comfort ratings which differed due to the noise at specific seat positions in the aircraft.

  4. Effects of anthropogenic water regulation and groundwater lateral flow on land processes

    NASA Astrophysics Data System (ADS)

    Zeng, Yujin; Xie, Zhenghui; Yu, Yan; Liu, Shuang; Wang, Linying; Zou, Jing; Qin, Peihua; Jia, Binghao

    2016-09-01

    Both anthropogenic water regulation and groundwater lateral flow essentially affect groundwater table patterns. Their relationship is close because lateral flow recharges the groundwater depletion cone, which is induced by over-exploitation. In this study, schemes describing groundwater lateral flow and human water regulation were developed and incorporated into the Community Land Model 4.5. To investigate the effects of human water regulation and groundwater lateral flow on land processes as well as the relationship between the two processes, three simulations using the model were conducted for the years 2003-2013 over the Heihe River Basin in northwestern China. Simulations showed that groundwater lateral flow driven by changes in water heads can essentially change the groundwater table pattern with the deeper water table appearing in the hillslope regions and shallower water table appearing in valley bottom regions and plains. Over the last decade, anthropogenic groundwater exploitation deepened the water table by approximately 2 m in the middle reaches of the Heihe River Basin and rapidly reduced the terrestrial water storage, while irrigation increased soil moisture by approximately 0.1 m3 m-3. The water stored in the mainstream of the Heihe River was also reduced by human surface water withdrawal. The latent heat flux was increased by 30 W m-2 over the irrigated region, with an identical decrease in sensible heat flux. The simulated groundwater lateral flow was shown to effectively recharge the groundwater depletion cone caused by over-exploitation. The offset rate is higher in plains than mountainous regions.

  5. Anthropogenic effects on a tropical forest according to the distance from human settlements

    PubMed Central

    Popradit, Ananya; Srisatit, Thares; Kiratiprayoon, Somboon; Yoshimura, Jin; Ishida, Atsushi; Shiyomi, Masae; Murayama, Takehiko; Chantaranothai, Pranom; Outtaranakorn, Somkid; Phromma, Issara

    2015-01-01

    The protection of tropical forests is one of the most urgent issues in conservation biology because of the rapid deforestation that has occurred over the last 50 years. Even in protected forests, the anthropogenic effects from newly expanding villages such as harvesting of medicinal plants, pasturing cattle and forest fires can induce environmental modifications, especially on the forest floor. We evaluated the anthropogenic effects of the daily activities of neighboring residents on natural forests in 12 plots extending from the village boundary into a natural forest in Thailand. The basal area per unit land area did not present a significant trend; however, the species diversity of woody plants decreased linearly towards the village boundary, which caused a loss of individual density because of severe declines in small saplings compared with adult trees and large saplings in proximity to the village. An analysis of tree-size categories indicates a lack of small samplings near the village boundary. The current forest appears to be well protected based on the adult tree canopy, but regeneration of the present-day forests is unlikely because of the loss of seedlings. PMID:26434950

  6. Effects of anthropogenic fragmentation on primary productivity and soil carbon storage in temperate mountain grasslands.

    PubMed

    Cojoc, Emilia Ionela; Postolache, Carmen; Olariu, Bogdan; Beierkuhnlein, Carl

    2016-11-01

    Habitat fragmentation is one of the most severe anthropogenic pressures exerted on ecosystem's biodiversity. Empirical studies to date focused with an overriding interest on the effects of habitat loss or habitat fragmentation per se on species richness patterns detrimental to biogeochemical processes. To account for changes in ecosystem fluxes, we investigated how anthropogenic fragmentation affects primary productivity and carbon storage in temperate mountain grasslands. A field study was conducted to assess the influence of grassland isolation on soil carbon stocks, N availability, species biomass, and plant functional groups distribution. We tested the hypothesis that increased isolation of grassland, within the land cover, decreases soil carbon stocks, and available N nutrient as well as aboveground biomass. Soil carbon concentration decreased with isolation but increased near the forest edge. We found significant differences in aboveground biomass distribution and relative contribution of plant functional groups between isolation conditions. The magnitude of edge effect on carbon stocks, N availability, and primary productivity intensified with increasing isolation as a consequence of the additive influence of edges. Our study reveals that the potential creation of artificially isolated patches diminished primary productivity, N availability, and C stocks. However, in highly managed landscapes, grazing pressure is an additional factor that changes biomass and nutrients patterns. We emphasize that spatial configuration of the landscape has a major role in modulating ecological flows and ecosystem service supply, in addition to changes in species richness.

  7. Occurrence of THM and NDMA precursors in a watershed: Effect of seasons and anthropogenic pollution.

    PubMed

    Aydin, Egemen; Yaman, Fatma Busra; Ates Genceli, Esra; Topuz, Emel; Erdim, Esra; Gurel, Melike; Ipek, Murat; Pehlivanoglu-Mantas, Elif

    2012-06-30

    In pristine watersheds, natural organic matter is the main source of disinfection by-product (DBP) precursors. However, the presence of point or non-point pollution sources in watersheds may lead to increased levels of DBP precursors which in turn form DBPs in the drinking water treatment plant upon chlorination or chloramination. In this study, water samples were collected from a lake used to obtain drinking water for Istanbul as well as its tributaries to investigate the presence of the precursors of two disinfection by-products, trihalomethanes (THM) and N-nitrosodimethylamine (NDMA). In addition, the effect of seasons and the possible relationships between these precursors and water quality parameters were evaluated. The concentrations of THM and NDMA precursors measured as total THM formation potential (TTHMFP) and NDMA formation potential (NDMAFP) ranged between 126 and 1523μg/L THM and <2 and 1648ng/L NDMA, respectively. Such wide ranges imply that some of the tributaries are affected by anthropogenic pollution sources, which is also supported by high DOC, Cl(-) and NH(3) concentrations. No significant correlation was found between the water quality parameters and DBP formation potential, except for a weak correlation between NDMAFP and DOC concentrations. The effect of the sampling location was more pronounced than the seasonal variation due to anthropogenic pollution in some tributaries and no significant correlation was obtained between the seasons and water quality parameters.

  8. Anthropogenic effects on a tropical forest according to the distance from human settlements.

    PubMed

    Popradit, Ananya; Srisatit, Thares; Kiratiprayoon, Somboon; Yoshimura, Jin; Ishida, Atsushi; Shiyomi, Masae; Murayama, Takehiko; Chantaranothai, Pranom; Outtaranakorn, Somkid; Phromma, Issara

    2015-10-05

    The protection of tropical forests is one of the most urgent issues in conservation biology because of the rapid deforestation that has occurred over the last 50 years. Even in protected forests, the anthropogenic effects from newly expanding villages such as harvesting of medicinal plants, pasturing cattle and forest fires can induce environmental modifications, especially on the forest floor. We evaluated the anthropogenic effects of the daily activities of neighboring residents on natural forests in 12 plots extending from the village boundary into a natural forest in Thailand. The basal area per unit land area did not present a significant trend; however, the species diversity of woody plants decreased linearly towards the village boundary, which caused a loss of individual density because of severe declines in small saplings compared with adult trees and large saplings in proximity to the village. An analysis of tree-size categories indicates a lack of small samplings near the village boundary. The current forest appears to be well protected based on the adult tree canopy, but regeneration of the present-day forests is unlikely because of the loss of seedlings.

  9. Anthropogenic effects on a tropical forest according to the distance from human settlements

    NASA Astrophysics Data System (ADS)

    Popradit, Ananya; Srisatit, Thares; Kiratiprayoon, Somboon; Yoshimura, Jin; Ishida, Atsushi; Shiyomi, Masae; Murayama, Takehiko; Chantaranothai, Pranom; Outtaranakorn, Somkid; Phromma, Issara

    2015-10-01

    The protection of tropical forests is one of the most urgent issues in conservation biology because of the rapid deforestation that has occurred over the last 50 years. Even in protected forests, the anthropogenic effects from newly expanding villages such as harvesting of medicinal plants, pasturing cattle and forest fires can induce environmental modifications, especially on the forest floor. We evaluated the anthropogenic effects of the daily activities of neighboring residents on natural forests in 12 plots extending from the village boundary into a natural forest in Thailand. The basal area per unit land area did not present a significant trend; however, the species diversity of woody plants decreased linearly towards the village boundary, which caused a loss of individual density because of severe declines in small saplings compared with adult trees and large saplings in proximity to the village. An analysis of tree-size categories indicates a lack of small samplings near the village boundary. The current forest appears to be well protected based on the adult tree canopy, but regeneration of the present-day forests is unlikely because of the loss of seedlings.

  10. The Anthropogenic `Greenhouse Effect': Greek Prospective Primary Teachers' Ideas About Causes, Consequences and Cures

    NASA Astrophysics Data System (ADS)

    Ikonomidis, Simos; Papanastasiou, Dimitris; Melas, Dimitris; Avgoloupis, Stavros

    2012-12-01

    This study explores the ideas of Greek prospective primary teachers about the anthropogenic greenhouse effect, particularly about its causes, consequences and cures. For this purpose, a survey was conducted: 265 prospective teachers completed a closed-form questionnaire. The results showed serious misconceptions in all areas (causes, consequences and cures). The most prominent misconception found by this survey is the conflation between the greenhouse effect and the ozone layer depletion, which is widely reported in the literature. There is also the notion that `good things' (like clean beaches) can help ameliorate the greenhouse effect, whereas `bad things' (like insecticides) can enhance it. One of the secondary results of the survey is that prospective teachers' main source of information about the greenhouse effect is school. This calls for educational interventions to fight misconceptions at the source. Some suggestions are presented in this paper. The results of this study are compared with the results of two similar studies conducted in the UK and in Turkey.

  11. Suggestions for revised definitions of noise quantities, including quantum effects

    NASA Astrophysics Data System (ADS)

    Kerr, A. R.

    1999-03-01

    Recent advances in millimeter- and submillimeter-wavelength receivers and the development of low-noise optical amplifiers focus attention on inconsistencies and ambiguities in the standard definitions of noise quantities and the procedures for measuring them. The difficulty is caused by the zero-point (quantum) noise hf/2 W/Hz, which is present even at absolute zero temperature, and also by the nonlinear dependence at low temperature of the thermal noise power of a resistor on its physical temperature, as given by the Planck law. Until recently, these effects were insignificant in all but the most exotic experiments, and the familiar Rayleigh-Jeans noise formula P=kT W/Hz could safely be used in most situations, Now, particularly in low-noise millimeter-wave and photonic devices, the quantum noise is prominent and the nonlinearity of the Planck law can no longer be neglected. The IEEE Standard Dictionary of Electrical and Electronics Terms gives several definitions of the noise temperature of a resistor or a port, which include: 1) the physical temperature of the resistor and 2) its available noise power density divided by Boltzmann's constant-definitions which are incompatible because of the nature of the Planck radiation law. In addition, there is no indication of whether the zero-point noise should be included as part of the noise temperature. Revised definitions of the common noise quantities are suggested, which resolve the shortcomings of the present definitions. The revised definitions have only a small effect on most RF and microwave measurements, but they provide a common consistent noise terminology from dc to light frequencies.

  12. Decomposition of climate change effects on ocean natural and anthropogenic carbon uptake.

    NASA Astrophysics Data System (ADS)

    Bernardello, Raffaele; Marinov, Irina; Palter, Jaime; Sarmiento, Jorge; Galbraith, Eric

    2013-04-01

    The ocean has been the only net sink of anthropogenic CO2 over the last 200 years, removing more than 30% of emitted anthropogenic carbon [Sabine et al., 2004]. The Southern Ocean accounts for up to half of this sink through the formation of various bottom, intermediate and mode water masses [Gruber et al., 2009]. Therefore, understanding the full range of global warming's possible consequences for the Earth system hinges on an understanding of the Southern Ocean's continued ability to serve as a carbon sink in the future. Many of the physical processes that are crucial to ocean carbon uptake and storage are expected to change under warming conditions, with consequences that are difficult to predict. The recent observed increase in the strength of the Southern Ocean Westerlies might enhance the anthropogenic carbon uptake through a more vigorous vertical mixing. However, this could also cause a decrease in natural carbon storage with a compensating effect. On the other hand, projected changes in buoyancy fluxes are expected to work in the opposite direction leading to a reduction of the vertical mixing. Finally, CO2 solubility at the sea surface will be affected by changes in temperature and salinity. We use a coupled atmosphere-ocean model (CM2Mc, Gallbraith et al., 2011) to perform a series of modeling experiments aimed to quantify the separate impact of these mechanisms on the various processes responsible for the functioning of the ocean carbon pumps. The experiments are based on the IPCC rcp8.5 scenario for the 21st century climate and consist in a combination of perturbations in which only one of the forcing factors is varying. This approach allows us to evaluate the relative importance of each process on the ability of the ocean to store carbon through the solubility and biological pumps. We also discuss the future climate projected changes in the relative importance of the Southern Ocean with respect to the global Ocean, for the total carbon uptake

  13. The Effect of Road Traffic Noise on Reaction Time

    PubMed Central

    Alimohammadi, Iraj; Zokaei, Mojtaba; Sandrock, Stephan

    2015-01-01

    Background: Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. Methods: Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. Results: Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (P<0.01). Introvert’s reaction time was more increased than that of extraverts. Conclusion: Traffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time. PMID:26634199

  14. The Effect of Road Traffic Noise on Reaction Time.

    PubMed

    Alimohammadi, Iraj; Zokaei, Mojtaba; Sandrock, Stephan

    2015-01-01

    Traffic noise is one of the main important sources in urban noise pollution, which causes various physiological and psychological effects that can cause disturbs in performance, sleep disturbances, hearing loss and impact on job performance. This study was conducted to verify the impact of road traffic noise on reaction time in terms of extraversion and sex. Traffic noise was measured and recorded in 10 arterial streets in Tehran, and then the recorded noise was emitted towards participants in an acoustic room. The participants were 80 (40 cases and 40 controls) students. Personality type was determined by Eysenck Personality Inventory (EPI) questioner. Reaction time before and after exposure to traffic noise was measured. Reaction time before exposure to traffic noise did not differ (P=0.437) significantly between introverts and extraverts. However, it was increased significantly in both groups after exposure to traffic noise (P<0.01). Introvert's reaction time was more increased than that of extraverts. Traffic noise augmented reaction time of both males and females. This study also revealed that exposure to traffic noise leads to increase in reaction time.

  15. Effects of duration and other noise characteristics on the annoyance caused by aircraft-flyover noise

    NASA Technical Reports Server (NTRS)

    Mccurdy, D. A.; Powell, C. A.

    1979-01-01

    A laboratory experiment was conducted to determine the effects of duration and other noise characteristics on the annoyance caused by aircraft-flyover noise. Duration, doppler shift, and spectra were individually controlled by specifying aircraft operational factors, such as velocity, altitude, and spectrum, in a computer synthesis of the aircraft-noise stimuli. This control allowed the separation of the effects of duration from the other main factors in the experimental design: velocity, tonal content, and sound pressure level. The annoyance of a set of noise stimuli which were comprised of factorial combinations of a 3 durations, 3 velocities, 3 sound pressure levels, and 2 tone conditions were judged. The judgements were made by using a graphical scale procedure similar to numerical category scaling. Each of the main factors except velocity was found to affect the judged annoyance significantly. The interaction of tonal content with sound pressure level was also found to be significant. The duration correction used in the effective-perceived-noise-level procedure, 3 dB per doubling of effective duration, was found to account most accurately for the effect of duration. No significant effect doppler shift was found.

  16. Noise and the Perceptual Filling-in effect

    PubMed Central

    Zomet, Ativ; Polat, Uri; Levi, Dennis M.

    2016-01-01

    Nearby collinear flankers increase the false alarm rate (reports of the target being present when it is not) in a Yes-No experiment. This effect has been attributed to “filling-in” of the target location due to increased activity induced by the flankers. According to signal detection theory, false alarms are attributed to noise in the visual nervous system. Here we investigated the effect of external noise on the filling-in effect by adding white noise to a low contrast Gabor target presented between two collinear Gabor flankers at a range of target-flanker separations. External noise modulates the filling-in effect, reducing visual sensitivity (d′) and increasing the filling-in effect (False Alarm rate). We estimated the amount of external noise at which the false alarm rate increases by the √2 (which we refer to as NFA). Across flank distances, both the false alarm rate and d′ (with no external noise) are correlated with NFA. These results are consistent with the notion that nearby collinear flankers add both signal and noise to the target location. The increased signal results in higher d′ values; the increased noise to higher false alarm rates (the filling effect). PMID:27103594

  17. Environmental versus anthropogenic effects on population adaptive divergence in the freshwater snail Lymnaea stagnalis.

    PubMed

    Bouétard, Anthony; Côte, Jessica; Besnard, Anne-Laure; Collinet, Marc; Coutellec, Marie-Agnès

    2014-01-01

    Repeated pesticide contaminations of lentic freshwater systems located within agricultural landscapes may affect population evolution in non-target organisms, especially in species with a fully aquatic life cycle and low dispersal ability. The issue of evolutionary impact of pollutants is therefore conceptually important for ecotoxicologists. The impact of historical exposure to pesticides on genetic divergence was investigated in the freshwater gastropod Lymnaea stagnalis, using a set of 14 populations from contrasted environments in terms of pesticide and other anthropogenic pressures. The hypothesis of population adaptive divergence was tested on 11 life-history traits, using Q(ST)-F(ST) comparisons. Despite strong neutral differentiation (mean F(ST) = 0.291), five adult traits or parameters were found to be under divergent selection. Conversely, two early expressed traits showed a pattern consistent with uniform selection or trait canalization, and four adult traits appeared to evolve neutrally. Divergent selection patterns were mostly consistent with a habitat effect, opposing pond to ditch and channel populations. Comparatively, pesticide and other human pressures had little correspondence with evolutionary patterns, despite hatching rate impairment associated with global anthropogenic pressure. Globally, analyses revealed high genetic variation both at neutral markers and fitness-related traits in a species used as model in ecotoxicology, providing empirical support for the need to account for genetic and evolutionary components of population response in ecological risk assessment.

  18. Research of the effects of TEC on UFPA noise performance

    NASA Astrophysics Data System (ADS)

    Jiang, Qiao; Xie, Guangzhong; Xiong, Lixia; Liao, Baobin; Que, Longcheng; Zhou, Yun; Lv, Jian

    2012-10-01

    Infrared detection technology plays a more and more important role in military and business. Uncooled infrared focal plane array (UFPA) is a kind of thermal detector, which detects the infrared radiation of target through the microbolometer's photoelectric conversion. Based on the thermal model of UFPA, stable and accordant substrate temperature of microbolometer array is extreme important to improve the UFPA's noise performance. After researching the effects of substrate temperature act on UFPA's noise performance and responsivity, a low noise data capture system with TEC controller for UFPA is designed. And a 320x240 microbolometer array's noise is tested with this system. With the TEC controller, the substrate temperature fluctuates at a margin of only 0.006 ºC. The test result shows that a 12.1% decrease in RMS noise, a 14.5% decrease in FPN noise and improvement of responsivity non-uniformity over time have been obtained after using TEC controller in UFPA.

  19. Laboratory and community studies of aircraft noise effects

    NASA Technical Reports Server (NTRS)

    Stephens, D. G.; Powell, C. A.

    1978-01-01

    The noise effects programs objective is to develop aircraft noise criteria and noise reduction methods for achieving greater community and passenger acceptance of air transportation systems. The approach consists of laboratory tests to subjectively evaluate the properties of aircraft-generated noise that are responsible for causing annoyance and field surveys to study the broader problems of community and passenger acceptability. The program is organized into two major thrusts: community acceptance and passenger acceptance. The community acceptance includes subjective response studies of single and multiple aircraft overflights as well as longer term community noise exposure. Emphasis is on the development of units and indices which accurately quantify annoyance. The passenger acceptance program includes studies to determine acceptably levels of interior noise and vibration for speech intelligibility and comfort of crew and passengers. Selected results from several recent studies are presented to indicate the nature, scope, and methods of the research program.

  20. Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar

    PubMed Central

    Farris, Zach J.; Golden, Christopher D.; Karpanty, Sarah; Murphy, Asia; Stauffer, Dean; Ratelolahy, Felix; Andrianjakarivelo, Vonjy; Holmes, Christopher M.; Kelly, Marcella J.

    2015-01-01

    The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting) affect carnivore occupancy across Madagascar’s largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species) and domestic dogs (Canis familiaris) had higher occupancy than half of the native carnivore species across Madagascar’s largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana) occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica). Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (x¯ = 90 individuals consumed/year), the ring-tailed vontsira (Galidia elegans) (x¯ = 58 consumed/year), and the fosa (Cryptoprocta ferox) (x¯ = 31 consumed/year). Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are

  1. Effects of rotating flows on combustion and jet noise.

    NASA Technical Reports Server (NTRS)

    Schwartz, I. R.

    1972-01-01

    Experimental investigations of combustion in rotating (swirling) flow have shown that the mixing and combustion processes were accelerated, flame length and noise levels significantly decreased, and flame stability increased relative to that obtained without rotation. Unsteady burning accompanied by a pulsating flame, violent fluctuating jet, and intense noise present in straight flow burning were not present in rotating flow burning. Correlations between theory and experiment show good agreement. Such effects due to rotating flows could lead to suppressing jet noise, improving combustion, reducing pollution, and decreasing aircraft engine size. Quantitative analysis of the aero-acoustic relationship and noise source characteristics are needed.-

  2. The effect of intensity noise on trapped-ion qubits

    NASA Astrophysics Data System (ADS)

    Brouard, Santiago; Plata, Jesus

    2004-05-01

    The effect of intensity fluctuations on laser-induced coupling of electronic and vibrational states of a trapped ion is studied analytically. Different types of noise relevant to the experiments are considered. The resulting decoherence phenomenology is shown to present nontrivial characteristics. Noise color leads to nonexponential decay of the coherences: after the initial decay, determined by the probability distribution, a transient period specific to the noise spectrum is apparent; at large times, exponential decay sets in for widely different noise properties. The detection of these features in the evolution of an initial coherent state of the vibrational mode is discussed.

  3. The Effects of Crosswind Flight on Rotor Harmonic Noise Radiation

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric; Sim, Ben W.

    2013-01-01

    In order to develop recommendations for procedures for helicopter source noise characterization, the effects of crosswinds on main rotor harmonic noise radiation are assessed using a model of the Bell 430 helicopter. Crosswinds are found to have a significant effect on Blade-Vortex Interaction (BVI) noise radiation when the helicopter is trimmed with the fuselage oriented along the inertial flight path. However, the magnitude of BVI noise remains unchanged when the pilot orients the fuselage along the aerodynamic velocity vector, crabbing for zero aerodynamic sideslip. The effects of wind gradients on BVI noise are also investigated and found to be smaller in the crosswind direction than in the headwind direction. The effects of crosswinds on lower harmonic noise sources at higher flight speeds are also assessed. In all cases, the directivity of radiated noise is somewhat changed by the crosswind. The model predictions agree well with flight test data for the Bell 430 helicopter captured under various wind conditions. The results of this investigation would suggest that flight paths for future acoustic flight testing are best aligned across the prevailing wind direction to minimize the effects of winds on noise measurements when wind cannot otherwise be avoided.

  4. Auditory intensity processing: Effect of MRI background noise.

    PubMed

    Angenstein, Nicole; Stadler, Jörg; Brechmann, André

    2016-03-01

    Studies on active auditory intensity discrimination in humans showed equivocal results regarding the lateralization of processing. Whereas experiments with a moderate background found evidence for right lateralized processing of intensity, functional magnetic resonance imaging (fMRI) studies with background scanner noise suggest more left lateralized processing. With the present fMRI study, we compared the task dependent lateralization of intensity processing between a conventional continuous echo planar imaging (EPI) sequence with a loud background scanner noise and a fast low-angle shot (FLASH) sequence with a soft background scanner noise. To determine the lateralization of the processing, we employed the contralateral noise procedure. Linearly frequency modulated (FM) tones were presented monaurally with and without contralateral noise. During both the EPI and the FLASH measurement, the left auditory cortex was more strongly involved than the right auditory cortex while participants categorized the intensity of FM tones. This was shown by a strong effect of the additional contralateral noise on the activity in the left auditory cortex. This means a massive reduction in background scanner noise still leads to a significant left lateralized effect. This suggests that the reversed lateralization in fMRI studies with loud background noise in contrast to studies with softer background cannot be fully explained by the MRI background noise. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Aircraft noise effects on sleep: mechanisms, mitigation and research needs.

    PubMed

    Basner, Mathias; Griefahn, Barbara; Berg, Martin van den

    2010-01-01

    There is an ample number of laboratory and field studies which provide sufficient evidence that aircraft noise disturbs sleep and, depending on traffic volume and noise levels, may impair behavior and well-being during the day. Although clinical sleep disorders have been shown to be associated with increased risk of cardiovascular diseases, only little is known about the long-term effects of aircraft noise disturbed sleep on health. National and international laws and guidelines try to limit aircraft noise exposure facilitating active and passive noise control to prevent relevant sleep disturbances and its consequences. Adopting the harmonized indicator of the European Union Directive 2002/49/EC, the WHO Night Noise Guideline for Europe (NNG) defines four Lnight , outside ranges associated with different risk levels of sleep disturbance and other health effects ( < 30, 30-40, 40-55, and> 55 dBA). Although traffic patterns differing in number and noise levels of events that lead to varying degrees of sleep disturbance may result in the same Lnight , simulations of nights with up to 200 aircraft noise events per night nicely corroborate expert opinion guidelines formulated in WHO's NNG. In the future, large scale field studies on the effects of nocturnal (aircraft) noise on sleep are needed. They should involve representative samples of the population including vulnerable groups like children and chronically ill subjects. Optimally, these studies are prospective in nature and examine the long-term consequences of noise-induced sleep disturbances. Furthermore, epidemiological case-control studies on the association of nocturnal (aircraft) noise exposure and cardiovascular disease are needed. Despite the existing gaps in knowledge on long-term health effects, sufficient data are available for defining limit values, guidelines and protection concepts, which should be updated with the availability of new data.

  6. Anthropogenic effects are associated with a lower persistence of marine food webs.

    PubMed

    Gilarranz, Luis J; Mora, Camilo; Bascompte, Jordi

    2016-02-12

    Marine coastal ecosystems are among the most exposed to global environmental change, with reported effects on species biomass, species richness and length of trophic chains. By combining a biologically informed food-web model with information on anthropogenic influences in 701 sites across the Caribbean region, we show that fishing effort, human density and thermal stress anomaly are associated with a decrease in local food-web persistence. The conservation status of the site, in turn, is associated with an increase in food-web persistence. Some of these associations are explained through effects on food-web structure and total community biomass. Our results unveil a hidden footprint of human activities. Even when food webs may seem healthy in terms of the presence and abundance of their constituent species, they may be losing the capacity to withstand further environmental degradation.

  7. Anthropogenic effects are associated with a lower persistence of marine food webs

    PubMed Central

    Gilarranz, Luis J.; Mora, Camilo; Bascompte, Jordi

    2016-01-01

    Marine coastal ecosystems are among the most exposed to global environmental change, with reported effects on species biomass, species richness and length of trophic chains. By combining a biologically informed food-web model with information on anthropogenic influences in 701 sites across the Caribbean region, we show that fishing effort, human density and thermal stress anomaly are associated with a decrease in local food-web persistence. The conservation status of the site, in turn, is associated with an increase in food-web persistence. Some of these associations are explained through effects on food-web structure and total community biomass. Our results unveil a hidden footprint of human activities. Even when food webs may seem healthy in terms of the presence and abundance of their constituent species, they may be losing the capacity to withstand further environmental degradation. PMID:26867790

  8. Compositional shifts in bacterial communities associated with the coral Palythoa caribaeorum due to anthropogenic effects.

    PubMed

    Paulino, Gustavo Vasconcelos Bastos; Broetto, Leonardo; Pylro, Victor Satler; Landell, Melissa Fontes

    2017-01-30

    Corals harbor abundant and diverse prokaryotic communities that may be strongly influenced by human activities, which in turn compromise the normal functioning of coral species and predispose them to opportunistic infections. In this study, we investigated the effect of sewage dumping on the bacterial communities associated with the soft coral Palythoa caribaeorum at two sites in the Brazilian coast. We observed a dominance of bacterial species classified as human pathogens at sites exposed to untreated sewage discharge. The microbial diversity of undisturbed sites was more homogeneous and diverse and showed greater abundance. In addition, bacterial communities differed substantially between the exposed and undisturbed areas. The microbial community associated with the samples collected from the exposed sites revealed the anthropogenic effect caused by organic matter from untreated sewage dumping, with an abundance of pathogenic bacterial species.

  9. Individual, population and community level effects of subtle anthropogenic contamination in estuarine meiobenthos.

    PubMed

    Rubal, Marcos; Guilhermino, Lúcia M; Medina, Matías H

    2009-10-01

    The study presented here searched for the level of taxonomic resolution required to detect the effects of low-level chronic pollution on estuarine meiobenthic communities. Meiofauna from two sites, with special attention to harpacticoid copepods, was analysed at different taxonomic levels of aggregation using uni- and multivariate methods. Adaptation processes that could buffer biodiversity disruptions were also considered through the analysis of fitness-related and tolerance traits in the harpacticoid copepod Paronychocamptus nanus. Results showed that uni- and multivariate analyses could be inadequate when assessing subtle anthropogenic contamination. Instead, the assessment of inter-population differences in tolerance to the main source of stress rises as a required procedure if potential effects of this type of contamination are being investigated. Specifically, a 96 h acute toxicity test performed with populations from the affected site appears as a faster and reliable general tool to assess impacts of low-level chronic pollution in estuaries.

  10. The effect of AM noise on correlation phase-noise measurements.

    PubMed

    Rubiola, Enrico; Boudot, Rodolphe

    2007-05-01

    We analyze the phase-noise measurement methods in which correlation and averaging is used to reject the background noise of the instrument. All the known methods make use of a mixer, used either as a saturated-phase detector or as a linear-synchronous detector. Unifortunately, AM noise is taken in through the power-to-dc-offset conversion mechanism that results from the mixer asymmetry. The measurement of some mixers indicates that the unwanted amplitude-to-voltage gain is of the order of 5-50 mV, which is 12-35 dB lower than the phase-to-voltage gain of the mixer. In addition, the trick of setting the mixer at a sweet point--off the quadrature condition--where the sensitivity to AM nulls, works only with microwave mixers. The HF-VHF mixers do not have this sweet point. Moreover, we prove that if the AM noise comes from the oscillator under test, it cannot be rejected by correlation. At least not with the schemes currently used. An example shows that at some critical frequencies the unwanted effect of AM noise is of the same order-if not greater--than the phase noise. Thus, experimental mistakes are around the corner.

  11. Effect of Noise in the Three-Parameter Logistic Model.

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    In a preceding research report, ONR/RR-82-1 (Information Loss Caused by Noise in Models for Dichotomous Items), observations were made on the effect of noise accommodated in different types of models on the dichotomous response level. In the present paper, focus is put upon the three-parameter logistic model, which is widely used among…

  12. RF noise suppression using the photodielectric effect in semiconductors

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.

    1969-01-01

    Technique using photodielectric effect of semiconductor in high-Q superconductive cavity gives initial improvement of 2-4 db in signal-to-noise enhancement of conventional RF communication systems. Wide band signal plus noise can be transmitted through a narrow-band cavity due to parametric perturbation of the cavity frequency or phase.

  13. Effect of Noise in the Three-Parameter Logistic Model.

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    In a preceding research report, ONR/RR-82-1 (Information Loss Caused by Noise in Models for Dichotomous Items), observations were made on the effect of noise accommodated in different types of models on the dichotomous response level. In the present paper, focus is put upon the three-parameter logistic model, which is widely used among…

  14. Effects of low levels of road traffic noise during the night: a laboratory study on number of events, maximum noise levels and noise sensitivity

    NASA Astrophysics Data System (ADS)

    Öhrström, E.

    1995-01-01

    The objective of the laboratory study presented here was to elucidate the importance of the number of noise events of a relatively low maximum noise level for sleep disturbance effects (body movements, subjective sleep quality, mood and performance). Twelve test persons slept eight nights under home-like laboratory settings. During four of these nights, each test person was exposed to 16, 32, 64 and 128 noise events respectively from recorded road traffic noise at a maximum noise level of 45 dB(A). All test persons (aged 20-42 years) considered themselves rather or very sensitive towards noise. The results show a significant decrease in subjective sleep quality at 32 noise events per night. At 64 noise events, 50% of the test persons experienced difficulties in falling asleep and, as compared with quiet nights, the time required to fall asleep was on average 12 minutes longer. The occurrence of body movements was significantly related to the reported number of awakenings, and the number of body movements was three times higher during the noisy periods of the night as compared with the quiet periods, indicating acute noise effects. The results of a vigilance test indicate that noise during the night might prolong the time needed to solve the test. Finally, and regardless of number of noise events, a significant increase in tiredness during the day was found after nights with noise exposure. In the paper comparisons are also made with earlier experiments using maximum noise levels of 50 and 60 dB(A).

  15. Effects of noise on models of spiny dendrites.

    PubMed

    Coutts, Emma J; Lord, Gabriel J

    2013-04-01

    We study the effects of noise in two models of spiny dendrites. Through the introduction of different types of noise to both the Spike-diffuse-spike (SDS) and Baer-Rinzel (BR) models we investigate the change in behaviour of the travelling wave solution present in both deterministic systems, as noise intensity increases. We show that the speed of wave propagation in both the SDS and BR models respectively differs as the noise intensity in the spine heads increases. In contrast the cable is very robust to noise and as such the speed shows very little variation from the deterministic system. We introduce a space-dependent spine density, ρ(x), to the original Baer-Rinzel model and show how this modified model can mimic behaviour (under influence of noise) of both original systems, through variation of one parameter. We also show that the correlation time and length scales of the noise can enhance propagation of travelling wave solutions where the white noise dominates the underlying signal and produces noise induced phenomena.

  16. Cardiorespiratory Responses to Acoustic Noise in Belugas.

    PubMed

    Lyamin, Oleg I; Korneva, Svetlana M; Rozhnov, Viatcheslav V; Mukhametov, Lev M

    2016-01-01

    To date, most research on the adverse effects of anthropogenic noise on marine mammals has focused on auditory and behavioral responses. Other responses have received little attention and are often ignored. In this study, the effect of acoustic noise on heart rate was examined in captive belugas. The data suggest that (1) heart rate can be used as a measure of physiological response (including stress) to noise in belugas and other cetaceans, (2) cardiac response is influenced by parameters of noise and adaptation to repeated exposure, and (3) cetacean calves are more vulnerable to the adverse effect of noise than adults.

  17. Attribution of spring snow water equivalent (SWE) changes over the northern hemisphere to anthropogenic effects

    NASA Astrophysics Data System (ADS)

    Jeong, Dae Il; Sushama, Laxmi; Naveed Khaliq, M.

    2017-06-01

    Snow is an important component of the cryosphere and it has a direct and important influence on water storage and supply in snowmelt-dominated regions. This study evaluates the temporal evolution of snow water equivalent (SWE) for the February-April spring period using the GlobSnow observation dataset for the 1980-2012 period. The analysis is performed for different regions of hemispherical to sub-continental scales for the Northern Hemisphere. The detection-attribution analysis is then performed to demonstrate anthropogenic and natural effects on spring SWE changes for different regions, by comparing observations with six CMIP5 model simulations for three different external forcings: all major anthropogenic and natural (ALL) forcings, greenhouse gas (GHG) forcing only, and natural forcing only. The observed spring SWE generally displays a decreasing trend, due to increasing spring temperatures. However, it exhibits a remarkable increasing trend for the southern parts of East Eurasia. The six CMIP5 models with ALL forcings reproduce well the observed spring SWE decreases at the hemispherical scale and continental scales, whereas important differences are noted for smaller regions such as southern and northern parts of East Eurasia and northern part of North America. The effects of ALL and GHG forcings are clearly detected for the spring SWE decline at the hemispherical scale, based on multi-model ensemble signals. The effects of ALL and GHG forcings, however, are less clear for the smaller regions or with single-model signals, indicating the large uncertainty in regional SWE changes, possibly due to stronger influence of natural climate variability.

  18. Attribution of spring snow water equivalent (SWE) changes over the northern hemisphere to anthropogenic effects

    NASA Astrophysics Data System (ADS)

    Jeong, Dae Il; Sushama, Laxmi; Naveed Khaliq, M.

    2016-07-01

    Snow is an important component of the cryosphere and it has a direct and important influence on water storage and supply in snowmelt-dominated regions. This study evaluates the temporal evolution of snow water equivalent (SWE) for the February-April spring period using the GlobSnow observation dataset for the 1980-2012 period. The analysis is performed for different regions of hemispherical to sub-continental scales for the Northern Hemisphere. The detection-attribution analysis is then performed to demonstrate anthropogenic and natural effects on spring SWE changes for different regions, by comparing observations with six CMIP5 model simulations for three different external forcings: all major anthropogenic and natural (ALL) forcings, greenhouse gas (GHG) forcing only, and natural forcing only. The observed spring SWE generally displays a decreasing trend, due to increasing spring temperatures. However, it exhibits a remarkable increasing trend for the southern parts of East Eurasia. The six CMIP5 models with ALL forcings reproduce well the observed spring SWE decreases at the hemispherical scale and continental scales, whereas important differences are noted for smaller regions such as southern and northern parts of East Eurasia and northern part of North America. The effects of ALL and GHG forcings are clearly detected for the spring SWE decline at the hemispherical scale, based on multi-model ensemble signals. The effects of ALL and GHG forcings, however, are less clear for the smaller regions or with single-model signals, indicating the large uncertainty in regional SWE changes, possibly due to stronger influence of natural climate variability.

  19. The effects of noise vocoding on speech quality perception.

    PubMed

    Anderson, Melinda C; Arehart, Kathryn H; Kates, James M

    2014-03-01

    Speech perception depends on access to spectral and temporal acoustic cues. Temporal cues include slowly varying amplitude changes (i.e. temporal envelope, TE) and quickly varying amplitude changes associated with the center frequency of the auditory filter (i.e. temporal fine structure, TFS). This study quantifies the effects of TFS randomization through noise vocoding on the perception of speech quality by parametrically varying the amount of original TFS available above 1500Hz. The two research aims were: 1) to establish the role of TFS in quality perception, and 2) to determine if the role of TFS in quality perception differs between subjects with normal hearing and subjects with sensorineural hearing loss. Ratings were obtained from 20 subjects (10 with normal hearing and 10 with hearing loss) using an 11-point quality scale. Stimuli were processed in three different ways: 1) A 32-channel noise-excited vocoder with random envelope fluctuations in the noise carrier, 2) a 32-channel noise-excited vocoder with the noise-carrier envelope smoothed, and 3) removal of high-frequency bands. Stimuli were presented in quiet and in babble noise at 18dB and 12dB signal-to-noise ratios. TFS randomization had a measurable detrimental effect on quality ratings for speech in quiet and a smaller effect for speech in background babble. Subjects with normal hearing and subjects with sensorineural hearing loss provided similar quality ratings for noise-vocoded speech.

  20. Effect of operating conditions on gearbox noise

    NASA Astrophysics Data System (ADS)

    Oswald, Fred B.; Zakrajsek, James J.; Townsend, Dennis P.; Atherton, William; Lin, Hsiang Hsi

    1992-04-01

    Low contact ratio spur gears were tested in the NASA gear noise rig to study the noise radiated from the top of the gearbox. The measured sound power from the gearbox top was obtained from a near field acoustic intensity scan taken at 63 nodes just above the surface. The sound power was measured at a matrix of 45 operating speeds and torque levels. Results are presented in the form of a spectral speed map and as a plot of sound power versus torque (at constant speed) and as sound power versus speed (at constant torque). Because of the presence of vibration modes, operating speed was found to have more impact on noise generation than torque level. A NASA gear dynamics code was used to compute the gear tooth dynamic overload at the same 45 operating conditions used for the experiment. Similar trends were found between the analytical results for dynamic tooth overload and experimental results for sound power. Dynamic analysis may be used to design high quality gears with profile relief optimized for minimum dynamic load and noise.

  1. Effects of background noise on earphone thresholds.

    PubMed

    Frank, T; Williams, D L

    1993-05-01

    Real-ear attenuation at threshold (REAT) and monaural pure-tone thresholds were determined for normally hearing adults using a supra-aural, Audiocup, and insert earphone. The thresholds were obtained in quiet and in background noises approximating the maximum permissible ambient noise levels (MPANLs) allowed in an audiometric test room specified by ANSI S3.1-1991 and OSHA (1983). The supra-aural REAT was less than the Audiocup, which was less than the insert earphone. The mean threshold shifts were negligible regardless of earphone type in the ANSI noise and for the insert earphone in the OSHA noise. Thresholds can be obtained down to 0 dB HL in ANSI 1991 MPANLs using a supra-aural, Audiocup, or insert earphone and in OSHA MPANLs using an insert earphone. However, the OSHA MPANLs are too high and the REAT is too low for a supra-aural earphone and Audiocup for testing down to 0 dB HL.

  2. Vision and photoentrainment in fishes: the effects of natural and anthropogenic perturbation.

    PubMed

    Collin, Shaun P; Hart, Nathan S

    2015-01-01

    Vision and photoentrainment in fishes are vital for feeding, avoiding predation, spatial orientation, navigation, social communication and the synchronization of many homeostatic functions such as activity patterns and sleep. The camera-like (image-forming) eyes of fishes are optimized to provide a clear view of their preferred ecological niche, while non-visual photoreceptors provide irradiance detection that mediates circadian photoentrainment, an endogenous time-keeping mechanism (biological clock) to respond to predictable changes in environmental conditions. Fish and fisheries are under pressure from both natural and anthropogenic perturbation, which in many cases alters the intensity and spectral composition of the light environment on which they depend for their survival. This review examines the effects of a changing light environment and turbidity on the health of fishes within a developmental and ecological context. Understanding the sensory environment of fishes is vital to predicting their responses and, ultimately, their resilience to environmental change and the potential for maintaining sustainable levels of biodiversity.

  3. The effect of microphone wind noise on the amplitude modulation of wind turbine noise and its mitigation.

    PubMed

    Kendrick, Paul; von Hünerbein, Sabine; Cox, Trevor J

    2016-07-01

    Microphone wind noise can corrupt outdoor recordings even when wind shields are used. When monitoring wind turbine noise, microphone wind noise is almost inevitable because measurements cannot be made in still conditions. The effect of microphone wind noise on two amplitude modulation (AM) metrics is quantified in a simulation, showing that even at low wind speeds of 2.5 m/s errors of over 4 dBA can result. As microphone wind noise is intermittent, a wind noise detection algorithm is used to automatically find uncorrupted sections of the recording, and so recover the true AM metrics to within ±2/±0.5 dBA.

  4. On the sensitivity of anthropogenic aerosol forcing to model-internal variability and parameterizing a Twomey effect

    NASA Astrophysics Data System (ADS)

    Fiedler, S.; Stevens, B.; Mauritsen, T.

    2017-06-01

    Despite efforts to accurately quantify the effective radiative forcing (ERF) of anthropogenic aerosol, the historical evolution of ERF remains uncertain. As a further step toward a better understanding of ERF uncertainty, the present study systematically investigates the sensitivity of the shortwave ERF at the top of the atmosphere to model-internal variability and spatial distributions of the monthly mean radiative effects of anthropogenic aerosol. For this, ensembles are generated with the atmospheric model ECHAM6.3 that uses monthly prescribed optical properties and changes in cloud-droplet number concentrations designed to mimic that associated with the anthropogenic aerosol using the new parameterization MACv2-SP. The results foremost highlight the small change in our best estimate of the global averaged all-sky ERF associated with a substantially different pattern of anthropogenic aerosol radiative effects from the mid-1970s (-0.51 Wm-2) and present day (-0.50 Wm-2). Such a small change in ERF is difficult to detect when model-internal year-to-year variability (0.32 Wm-2 standard deviation) is considered. A stable estimate of all-sky ERF requires ensemble simulations, the size of which depends on the targeted precision, confidence level, and the magnitude of model-internal variability. A larger effect of the pattern of the anthropogenic aerosol radiative effects on the globally averaged all-sky ERF (15%) occurs with a strong Twomey effect through lowering the background aerosol optical depth in regions downstream of major pollution sources. It suggests that models with strong aerosol-cloud interactions could show a moderate difference in the global mean ERF associated with the mid-1970s to present-day change in the anthropogenic aerosol pattern.

  5. Effects of anthropogenic nitrogen input on the aquatic food webs of river ecosystem in central Japan

    NASA Astrophysics Data System (ADS)

    Ohte, N.; Togashi, H.; Tokuchi, N.; Yoshimura, M.; Kato, Y.; Ishikawa, N. F.; Osaka, K.; Kondo, M.; Tayasu, I.

    2014-12-01

    To evaluate the impact of the anthropogenic nitrogen input to the river ecosystem, we conducted the monitoring on nutrient status of river waters and food web structures of aquatic organisms. Especially, changes of sources and concentration of nitrate (NO3-) in river water were focused to evaluate the impact of anthropogenic nitrogen loadings from agricultural and residential areas. Stable nitrogen isotope ratio (δ15N) of aquatic organisms has also intensively been monitored not only to describe their food web structure, but also to detect the influences of extraneous nitrogen inputs. Field samplings an observation campaigns were conducted in the Arida river watershed located in central part of Japan at four different seasons from September 2011 to October 2012. Five observation points were set from headwaters to the point just above the brackish waters starts. Water samples for chemical analysis were taken at the observation points for each campaign. Organisms including leaf litters, benthic algae, aquatic insects, crustacean, and fishes were sampled at each point quantitatively. Results of the riverine survey utilizing 5 regular sampling points showed that δ15N of nitrate (NO3-) increased from forested upstream (˜2 ‰) to the downstream (˜7 ‰) due to the sewage loads and fertilizer effluents from agricultural area. Correspondingly the δ15N of benthic algae and aquatic insects increased toward the downstream. This indicates that primary producers of each reach strongly relied on the local N sources and it was utilized effectively in their food web. Simulation using a GIS based mixing model considering the spatial distributions of human population density and fertilizer effluents revealed that strongest impacts of N inputs was originated from organic fertilizers applied to orchards in the middle to lower parts of catchment. Differences in δ15N between primary producers and predators were 6-7 ‰ similarly at all sampling points. Food web structural

  6. Assessing the effects of anthropogenic stressors on Puget Sound flatfish populations

    NASA Astrophysics Data System (ADS)

    Johnson, Lyndal L.; Landahl, John T.; Kubin, Leslie A.; Horness, Beth H.; Myers, Mark S.; Collier, Tracy K.; Stein, John E.

    1998-03-01

    Puget Sound is an estuary in the northwestern United States which serves as the habitat for a number of recreationally and commercially important species of flatfish. Over the past 100 years, there has been substantial urban and industrial development within this region, resulting in heavy inputs of chemical contaminants at selected sites, as well as significant loss or alteration of marine habitat. Studies show that feral flatfish in Puget Sound are experiencing a range of biological effects due to chemical contaminant exposure, including reproductive dysfunction, altered immune competence, and development of toxicopathic diseases, and there is some evidence of reduced survival in fish from urban areas of Puget Sound from increased infectious and toxicopathic disease. Puget Sound sole are also subject to other anthropogenic stressors, such as fishing pressure or alteration of nearshore nursery habitats. The cumulative impact of these stressors on flatfish abundance in Puget Sound, however, is poorly understood. In a series of field and laboratory studies, we determined vital rates and other life history parameters in English sole ( Pleuronectes vetulus) subpopulations from urban and non-urban sites in Puget Sound, and are using this information to estimate potential population level impacts of anthropogenic stressors, with age and stage-based Leslie-matrix models. Initial results suggest that declines in the fecundity component of the model, as observed in field studies of fish from contaminated sites, could reduce the size of sub-populations in these areas if the loss of recruits is not offset by density-dependent changes in recruitment, immigration, or other compensating mechanisms. Studies on flatfish species from a variety of sites in Europe and North America suggest that contaminant-related disease and reproductive impairment are widespread in this group of fish, although substantial differences in sensitivity have been observed, even among closely related

  7. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multidecadal strong and weak monsoon stages

    DOE PAGES

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; ...

    2016-06-18

    Industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, and so the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. In order to further understand the aerosol-EASM interaction, we investigate the impacts of anthropogenic aerosols on the EASM during the multidecadal strong (1950–1977) and weak (1978–2000) EASM stages using the Community Atmospheric Model 5.1. Numerical experiments are conducted for the whole period, including the two different EASM stages, with present day (PD, year 2000) and preindustrial (PI, year 1850) aerosol emissions, as well as the observed time-varying aerosolmore » emissions. A comparison of the results from PD and PI shows that, with the increase in anthropogenic aerosols, the large-scale EASM intensity is weakened to a greater degree (-9.8%) during the weak EASM stage compared with the strong EASM stage (-4.4%). The increased anthropogenic aerosols also result in a significant reduction in precipitation over North China during the weak EASM stage, as opposed to a statistically insignificant change during the strong EASM stage. Because of greater aerosol loading and the larger sensitivity of the climate system during weak EASM stages, the aerosol effects are more significant during these EASM stages. Moreover, these results suggest that anthropogenic aerosols from the same aerosol emissions have distinct effects on the EASM and the associated precipitation between the multidecadal weak and strong EASM stages.« less

  8. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multidecadal strong and weak monsoon stages

    NASA Astrophysics Data System (ADS)

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; Li, Jiandong; Wang, Zhaosheng; Liu, Yangang

    2016-06-01

    Because industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. To further understand the aerosol-EASM interaction, we investigate the impacts of anthropogenic aerosols on the EASM during the multidecadal strong (1950-1977) and weak (1978-2000) EASM stages using the Community Atmospheric Model 5.1. Numerical experiments are conducted for the whole period, including the two different EASM stages, with present day (PD, year 2000) and preindustrial (PI, year 1850) aerosol emissions, as well as the observed time-varying aerosol emissions. A comparison of the results from PD and PI shows that, with the increase in anthropogenic aerosols, the large-scale EASM intensity is weakened to a greater degree (-9.8%) during the weak EASM stage compared with the strong EASM stage (-4.4%). The increased anthropogenic aerosols also result in a significant reduction in precipitation over North China during the weak EASM stage, as opposed to a statistically insignificant change during the strong EASM stage. Because of greater aerosol loading and the larger sensitivity of the climate system during weak EASM stages, the aerosol effects are more significant during these EASM stages. These results suggest that anthropogenic aerosols from the same aerosol emissions have distinct effects on the EASM and the associated precipitation between the multidecadal weak and strong EASM stages.

  9. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multidecadal strong and weak monsoon stages

    SciTech Connect

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; Li, Jiandong; Wang, Zhaosheng; Liu, Yangang

    2016-06-18

    Industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, and so the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. In order to further understand the aerosol-EASM interaction, we investigate the impacts of anthropogenic aerosols on the EASM during the multidecadal strong (1950–1977) and weak (1978–2000) EASM stages using the Community Atmospheric Model 5.1. Numerical experiments are conducted for the whole period, including the two different EASM stages, with present day (PD, year 2000) and preindustrial (PI, year 1850) aerosol emissions, as well as the observed time-varying aerosol emissions. A comparison of the results from PD and PI shows that, with the increase in anthropogenic aerosols, the large-scale EASM intensity is weakened to a greater degree (-9.8%) during the weak EASM stage compared with the strong EASM stage (-4.4%). The increased anthropogenic aerosols also result in a significant reduction in precipitation over North China during the weak EASM stage, as opposed to a statistically insignificant change during the strong EASM stage. Because of greater aerosol loading and the larger sensitivity of the climate system during weak EASM stages, the aerosol effects are more significant during these EASM stages. Moreover, these results suggest that anthropogenic aerosols from the same aerosol emissions have distinct effects on the EASM and the associated precipitation between the multidecadal weak and strong EASM stages.

  10. Distinct effects of anthropogenic aerosols on the East Asian summer monsoon between multidecadal strong and weak monsoon stages

    SciTech Connect

    Xie, Xiaoning; Wang, Hongli; Liu, Xiaodong; Li, Jiandong; Wang, Zhaosheng; Liu, Yangang

    2016-06-18

    Industrial emissions of anthropogenic aerosols over East Asia have greatly increased in recent decades, and so the interactions between atmospheric aerosols and the East Asian summer monsoon (EASM) have attracted enormous attention. In order to further understand the aerosol-EASM interaction, we investigate the impacts of anthropogenic aerosols on the EASM during the multidecadal strong (1950–1977) and weak (1978–2000) EASM stages using the Community Atmospheric Model 5.1. Numerical experiments are conducted for the whole period, including the two different EASM stages, with present day (PD, year 2000) and preindustrial (PI, year 1850) aerosol emissions, as well as the observed time-varying aerosol emissions. A comparison of the results from PD and PI shows that, with the increase in anthropogenic aerosols, the large-scale EASM intensity is weakened to a greater degree (-9.8%) during the weak EASM stage compared with the strong EASM stage (-4.4%). The increased anthropogenic aerosols also result in a significant reduction in precipitation over North China during the weak EASM stage, as opposed to a statistically insignificant change during the strong EASM stage. Because of greater aerosol loading and the larger sensitivity of the climate system during weak EASM stages, the aerosol effects are more significant during these EASM stages. Moreover, these results suggest that anthropogenic aerosols from the same aerosol emissions have distinct effects on the EASM and the associated precipitation between the multidecadal weak and strong EASM stages.

  11. Effect of individual blade control on noise radiation

    NASA Technical Reports Server (NTRS)

    Swanson, S. M.; Jacklin, Stephen A.; Niesl, G.; Blaas, Achim; Kube, R.

    1995-01-01

    In a joint research program of NASA Ames Research Center, ZF Luftfahrttechnik, the German Aerospace Research Establishment (DLR), and EUROCOPTER Deutschland, a wind tunnel test was performed to evaluate the effects of Individual Blade Control (IBC) on rotor noise. This test was conducted in the 40x80 ft wind tunnel at NASA Ames Research Center, utilizing a full scale MBB-BO 105 four-bladed rotor system. Three microphones were installed for determination of the radiated noise, two of them on a moveable traverse below the advancing blade side and one in a fixed location below the retreating side. Acoustic results are presented for flight conditions with Blade-Vortex-Interaction (BVI) noise radiation. High noise level reductions were measured for single harmonic control inputs. In addition to the single harmonic inputs, multi-harmonic inputs were evaluated by superimposing 2/rev to 6/rev harmonics. For the first time the efficiency of sharp wavelets (60 deg and 90 deg width) on acoustic noise were measured. In order to achieve an adequate wavelet shape at the blade tip, corrections were made to account for the blade torsional behavior. In parallel with the acoustic measurements, vibratory loads were measured during the BVI flight condition to correlate the effects of IBC on noise and vibrations. It is shown how noise levels and vibrations are affected by specific IBC control inputs. In addition, correlations are made between noise levels and acoustic time histories with IBC phase and amplitude variations. For one IBC input mode with high noise reducing efficiency, a sweep of the moveable microphone traverse below the advancing side shows the effect on BVI noise directivity.

  12. Effects of a traffic noise background on judgements of aircraft noise

    NASA Technical Reports Server (NTRS)

    Powell, C. A.; Rice, C. G.

    1974-01-01

    A study was conducted in which subjects judged aircraft noises in the presence of road traffic background noise. Two different techniques for presenting the background noises were evaluated. For one technique, the background noise was continuous over the whole of a test session. For the other, the background noise was changed with each aircraft noise. A range of aircraft noise levels and traffic noise levels were presented to simulate typical indoor levels.

  13. Near-field noise prediction for aircraft in cruising flight: Methods manual. [laminar flow control noise effects analysis

    NASA Technical Reports Server (NTRS)

    Tibbetts, J. G.

    1979-01-01

    Methods for predicting noise at any point on an aircraft while the aircraft is in a cruise flight regime are presented. Developed for use in laminar flow control (LFC) noise effects analyses, they can be used in any case where aircraft generated noise needs to be evaluated at a location on an aircraft while under high altitude, high speed conditions. For each noise source applicable to the LFC problem, a noise computational procedure is given in algorithm format, suitable for computerization. Three categories of noise sources are covered: (1) propulsion system, (2) airframe, and (3) LFC suction system. In addition, procedures are given for noise modifications due to source soundproofing and the shielding effects of the aircraft structure wherever needed. Sample cases, for each of the individual noise source procedures, are provided to familiarize the user with typical input and computed data.

  14. Effects of aircraft noise on flight and ground structures

    NASA Technical Reports Server (NTRS)

    Mixson, J. S.; Mayes, W. H.; Willis, C. M.

    1976-01-01

    Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft.

  15. Potential effects of anthropogenic greenhouse gases on avian habitas and populations in the northern Great Plains

    SciTech Connect

    Larson, D.L. )

    1994-04-01

    Biotic response to the buildup of greenhouse gases in Earth's atmosphere is considerably more complex than an adjustment to changing temperature and precipitation. The fertilization effect CO[sub 2] has on some plants, the impact UVB radiation has on health and productivity of organisms, and the resulting changes in competitive balance and trophic structure must also be considered. The intent of this paper is to review direct and indirect effects of anthropogenic greenhouse gases on wildlife, and to explore possible effects on populations of birds and their habitats in the northern Great Plains. Many of the potential effects of increasing greenhouse gases, such as declining plant nutritional value, changes in timing of insect emergence, and fewer and saltier wetlands, foreshadow a decline in avian populations on the Great Plains. However, other possible effects such as increased drought resistance and water use efficiency of vegetation, longer growing seasons, and greater overall plant biomass promise at least some mitigation. Effects of multiple simultaneous perturbations such as can be expected under doubled CO[sub 2] scenarios will require substantial basic research to clarify. 113 refs., 1 fig.

  16. Potential effects of anthropogenic greenhouse gases on avian habitats and populations in the northern Great Plains

    USGS Publications Warehouse

    Larson, Diane L.

    1994-01-01

    Biotic response to the buildup of greenhouse gases in Earth's atmosphere is considerably more complex than an adjustment to changing temperature and precipitation. The fertilization effect carbon dioxide has on some plants, the impact UVB radiation has on health and productivity of organisms, and the resulting changes in competitive balance and trophic structure must also be considered. The intent of this paper is to review direct and indirect effects of anthropogenic greenhouse gases on wildlife, and to explore possible effects on populations of birds and their habitats in the northern Great Plains.Many of the potential effects of increasing greenhouse gases, such as declining plant nutritional value, changes in timing of insect emergence, and fewer and saltier wetlands, foreshadow a decline in avian populations on the Great Plains. However, other possible effects such as increased drought resistance and water use efficiency of vegetation, longer growing seasons, and greater overall plant biomass promise at least some mitigation. Effects of multiple simultaneous perturbations such as can be expected under doubled carbon dioxide scenarios will require substantial basic research to clarify.

  17. Aircraft noise: effects on macro- and microstructure of sleep.

    PubMed

    Basner, Mathias; Glatz, Christian; Griefahn, Barbara; Penzel, Thomas; Samel, Alexander

    2008-05-01

    The effects of aircraft noise on sleep macrostructure (Rechtschaffen and Kales) and microstructure (American Sleep Disorders Association [ASDA] arousal criteria) were investigated. For each of 10 subjects (mean age 35.3 years, 5 males), a baseline night without aircraft noise (control), and two nights with exposure to 64 noise events with a maximum sound pressure level (SPL) of either 45 or 65 dBA were chosen. Spontaneous and noise-induced alterations during sleep classified as arousals (ARS), changes to lighter sleep stages (CSS), awakenings including changes to sleep stage 1 (AS1), and awakenings (AWR) were analyzed. The number of events per night increased in the order AWR, AS1, CSS, and ARS under control conditions as well as under the two noise conditions. Furthermore, probabilities for sleep disruptions increased with increasing noise level. ARS were observed about fourfold compared to AWR, irrespective of control or noise condition. Under the conditions investigated, different sleep parameters show different sensitivities, but also different specificities for noise-induced sleep disturbances. We conclude that most information on sleep disturbances can be achieved by investigating robust classic parameters like AWR or AS1, although ASDA electroencephalographic (EEG) arousals might add relevant information in situations with low maximum SPLs, chronic sleep deprivation or chronic exposure.

  18. Physiological effects of railway vibration and noise on sleep.

    PubMed

    Smith, Michael G; Croy, Ilona; Ögren, Mikael; Hammar, Oscar; Lindberg, Eva; Persson Waye, Kerstin

    2017-05-01

    This paper evaluates the relative contribution of vibration and noise from railway on physiological sleep outcomes. Vibration from railway freight often accompanies airborne noise, yet is almost totally absent in the existing literature. In an experimental investigation, 23 participants, each sleeping for six nights in the laboratory, were exposed to 36 simulated railway freight pass-bys per night with vibration alone (aWd,max = 0.0204 ms(-2)), noise alone (LAF,max = 49.8 dB), or both vibration and noise simultaneously. A fourth exposure night involved 52 pass-bys with concurrent vibration and noise. Sleep was measured with polysomnography. Cardiac activity was measured with electrocardiography. The probability of cortical arousals or awakenings was greater following all exposures, including vibration alone, than spontaneous reaction probability (p < 0.05). The effects of vibration exposure and noise exposure on changes of sleep stage and arousals were directly additive. Vibration and noise exposure both induced heart rate acceleration above spontaneously expected fluctuations at baseline. The results indicate that vibration and noise are processed in the brain separately yet in parallel, with both contributing towards the likelihood of sleep disruption. The findings show that vibration is of importance when considering the impact of railway freight on sleep.

  19. Differential effects of white noise in cognitive and perceptual tasks

    PubMed Central

    Herweg, Nora A.; Bunzeck, Nico

    2015-01-01

    Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (Experiments 1–3). In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (Experiment 4). In a modified Posner task (Experiment 5), the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation. PMID:26579024

  20. Differential effects of white noise in cognitive and perceptual tasks.

    PubMed

    Herweg, Nora A; Bunzeck, Nico

    2015-01-01

    Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (Experiments 1-3). In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (Experiment 4). In a modified Posner task (Experiment 5), the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

  1. Anthropogenic effects on the subsurface thermal and groundwater environments in Osaka, Japan and Bangkok, Thailand.

    PubMed

    Taniguchi, Makoto; Shimada, Jun; Fukuda, Yoichi; Yamano, Makoto; Onodera, Shin-ichi; Kaneko, Shinji; Yoshikoshi, Akihisa

    2009-04-15

    Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters.

  2. Effect of anthropogenic activities on atmospheric 14C content and radiocarbon chronologies of the future.

    NASA Astrophysics Data System (ADS)

    Hajdas, Irka

    2017-04-01

    Radiocarbon (14C) is a naturally produced radioactive isotope of carbon (T1/2=5700 yrs), which is continuously produced in the atmosphere. This occur in a reaction of thermal neutrons, which are secondary particles, products of cosmic rays reactions with the atmosphere, with nitrogen that is commonly present in the atmosphere. Until the mid 19th century the natural concentration showed temporal variability around the mean value (14C / 12C ratio =1.8 x 10-12). However anthropogenic activity created 2 types effects that are changing the 14C concentration of the atmosphere. Industrial revolution triggered adding 14C free (old) carbon that originates from the burning of fossil fuels (Suess effect). This in the late 19th century and early 20th century atmosphere was becoming older. The nuclear tests in the 1950ties caused additional production of radiocarbon atoms (artificial). The effect has been almost double of the natural production and created an excess 14C activity in the atmosphere and in terrestrial carbon bearing materials. The bomb produced 14C has been identified soon after the tests started but the peak (ca. 100% above the normal levels) reached its maximum in 1963 in the northern Hemisphere where most of the tests took place. In the southern Hemisphere the bomb peak reached lower values (ca. 80 % of normal level) and was delayed by ca. 2 years. After the ban on nuclear tests the atmospheric 14C content began to decrease mainly due to the uptake by the ocean but also due to the above mentioned addition old carbon. Continuous monitoring of the atmospheric 14C ratio during the years that followed the nuclear tests, provide basis for environmental studies. Applications range from studies of ocean circulation, CO2 uptake, carbon storage in soils and peat, root turn over time to the medical, forensic and detection of forgeries. However, the so called ' 14C bomb peak' nearly disappeared due to the combined effect of ocean uptake of CO2 and an input to the

  3. Protective effect of propofol on noise-induced hearing loss.

    PubMed

    Wen, Jian; Duan, Na; Wang, Qiang; Jing, Gui-Xia; Xiao, Ying

    2017-02-15

    Iatrogenic noise produced by mastoid or craniotomy drills may cause hearing damage, which is induced by the generation of reactive oxygen species (ROS) and the reduction of cochlear blood flow (CoBF). This study investigated whether propofol could reduce noise-induced hearing loss (NIHL) in a guinea pig model. Sixty-four male pigmented guinea pigs were randomly and equally divided into 4 groups: control, noise, propofol and propofol+noise. Propofol was infused intravenously for 20min prior to noise exposure with a loading dose of 5mg·kg(-1) for 5min and a maintenance infusion of 20mg·kg(-1)·h(-1) for 135min. For noise exposure, an octave band noise at a 124dB sound pressure level (SPL) was administered to animals for 2h. The mean arterial pressure (MAP) and CoBF were monitored continuously. Auditory function was measured by the level of distortion product otoacoustic emission (DPOAE) before and at 1h, 72h and 240h after noise exposure. Cochlear levels of 8-iso-Prostaglandin F2alpha (8-iso-PGF2α) were measured immediately after the termination of noise exposure. Cochlear silver nitrate staining and outer hair cell (OHC) counting were performed after the final functional test. Noise exposure caused decreases in the CoBF and DPOAE amplitudes, over-generation of 8-iso-PGF2α and the loss of OHCs. Pre-treatment with propofol significantly increased the CoBF and DPOAE amplitudes, decreased 8-iso-PGF2α and the loss of OHCs. Propofol exerted protective effects against NIHL in this animal model by suppressing a lipid peroxidation reaction and improving CoBF. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Effects of Road Traffic Noise on Inhabitants of Tokyo

    NASA Astrophysics Data System (ADS)

    Yoshida, T.; Osada, Y.; Kawaguchi, T.; Hoshiyama, Y.; Yoshida, K.; Yamamoto, K.

    1997-08-01

    A questionnaire-based study was performed in an area of about 16 ha near a main road in Tokyo to elucidate any relations between road traffic noise and the effects of this noise among women living on both sides of the road. Questions concerned annoyance, sleep disturbance, interference with daily activities, health-related symptoms and disease histories. 366 inhabitants were analyzed. Dose-response relationships were found in high reported responses to noisiness, annoyance, dissatisfaction with the nearby environment and interference with listening to TV, conversation and reading. It was also found that the number of high responses to questions increases clearly at noise levels above 70 dB(A),Leq(24h), with regard to interference with thinking and sleep disturbance (waking during the night), fatigue, headache, gastroenteric disorders, loss of appetite, depression and irritation. Furthermore, there was an increase in reports of disease histories with noise above 70 dB(A) for climacteric disturbances, and at noise above 65 dB(A) for deafness, heart disease and hypercholestrolemia. These all suggest that noise may be related to the health status of inhabitants living in areas with heavy road traffic. A noise level of 65 dB(A) or 70 dB(A) inLeq(24h)was the critical point above which respondents indicated increased effects on health and reports of disease increased.

  5. Symmetric airfoil geometry effects on leading edge noise.

    PubMed

    Gill, James; Zhang, X; Joseph, P

    2013-10-01

    Computational aeroacoustic methods are applied to the modeling of noise due to interactions between gusts and the leading edge of real symmetric airfoils. Single frequency harmonic gusts are interacted with various airfoil geometries at zero angle of attack. The effects of airfoil thickness and leading edge radius on noise are investigated systematically and independently for the first time, at higher frequencies than previously used in computational methods. Increases in both leading edge radius and thickness are found to reduce the predicted noise. This noise reduction effect becomes greater with increasing frequency and Mach number. The dominant noise reduction mechanism for airfoils with real geometry is found to be related to the leading edge stagnation region. It is shown that accurate leading edge noise predictions can be made when assuming an inviscid meanflow, but that it is not valid to assume a uniform meanflow. Analytic flat plate predictions are found to over-predict the noise due to a NACA 0002 airfoil by up to 3 dB at high frequencies. The accuracy of analytic flat plate solutions can be expected to decrease with increasing airfoil thickness, leading edge radius, gust frequency, and Mach number.

  6. The effect of extrinsic noise on cellular decision making

    NASA Astrophysics Data System (ADS)

    Roberts, Elijah; Assaf, Michael; Luthey-Schulten, Zaida; Goldenfeld, Nigel

    2013-03-01

    Many cellular processes are not deterministic, i.e., genetically identical cells can display different phenotypic behavior even in identical environments. Such processes involve cellular decision making, in which individual cells randomly make choices determining their fate. One view is that the stochastic nature of cellular decision making is due to noise present in the biomolecular interaction networks. Most previous work has focused on the role of intrinsic noise of these networks. Yet, especially in the high copy-number regime, extrinsic noise may be much more significant, likely governing the overall dynamics. Here we develop a theoretical framework describing the combined effect of intrinsic and extrinsic noise on the stochastic dynamics of genetic switches responsible for cellular decision making. We do so by devising a semi-classical theory accounting for extrinsic noise as an effective species. Our theory, corroborated by extensive Monte-Carlo simulations, is tested on a simple bistable self-regulating gene model, and is then generalized to gain insight on the behavior of the lac genetic switch under extrinsic noise. We show that extrinsic noise not only significantly lowers the escape time from a phenotypic state, but can fundamentally change the actual escape process.

  7. Correlation between model-calculated anthropogenic aerosols and satellite-derived cloud optical depths: Indication of indirect effect?

    NASA Astrophysics Data System (ADS)

    Chameides, W. L.; Luo, C.; Saylor, R.; Streets, D.; Huang, Y.; Bergin, M.; Giorgi, F.

    2002-05-01

    is a mechanistic coupling between anthropogenic aerosol concentrations and cloud optical properties; one such mechanism is the so-called first and second indirect effect by which aerosols enhance the optical depths and albedos of clouds by increasing the number of droplets within clouds and suppressing precipitation from clouds, respectively. The regressions further suggest that the cloud optical depths increase on average by 0.16 for each 1 mg m-2 increase in the column-integrated anthropogenic aerosol burden. Simple box-model calculations suggest that this is equivalent to a cooling over the model domain from anthropogenic aerosols via the indirect effect that is a factor of about 1.5 times that from the direct effect. Accounting for a possible underestimate in model-simulated aerosol concentrations over the model domain of as much as a factor of 0.6 would lower the estimated cooling from the indirect effect to about 1 times that from the direct effect. In contrast to the results using ISSCP-derived cloud optical depths, the correlation between the model-calculated anthropogenic aerosols and average cloud amount over the model domain was relatively weak and inconsistent. This result arose perhaps because of a cancelling of the competing influences on cloud lifetime and frequency by the second indirect effect and the so-called semi direct effect (i.e., the suppression of clouds by absorbing aerosols).

  8. Effects of quantum noise in a dye-laser model

    NASA Astrophysics Data System (ADS)

    Jia, Ya; Li, Jia-Rong

    1997-03-01

    The steady-state properties of a dye laser model with white quantum noise and strongly colored pump noise are investigated. An effective diffusion coefficient in the steady state is presented. Our coefficient differs from that of Fox and Roy [Phys. Rev. A 35, 1838 (1987)]. We compare our results with the measurements and simulations of Lett, Short, and Mandel [Phys. Rev. Lett. 52, 341 (1984)], and the results of Fox and Roy, respectively. We find that the quantum noise plays an important role in the steady-state analysis of laser fluctuations below and near threshold.

  9. Effects of Simulated Flight on Fan Noise Suppression

    NASA Technical Reports Server (NTRS)

    Heidmann, M. F.; Dietrich, D. A.

    1977-01-01

    Attenuation properties of three treated fan inlets were evaluated. Tunnel flow simulated the inflow clean-up effect on source noise observed in flight and allowed observation of the blade passage frequency tone cut-off phenomenon. Acoustic data consisted of isolated inlet noise measured in the far field at two fixed positions and with traverses at four frequencies. Attenuation and source noise properties with and without flight simulation are compared and discussed. Averaged attenuation properties showed relative agreement of the inlets with their design intent, however, tunnel flow significantly affected the attenuation spectra.

  10. Photon-noise effect on detection in coherent active images.

    PubMed

    Réfrégier, Philippe; Goudail, François; Delyon, Guillaume

    2004-01-15

    We analyze photon-noise effects on target detection performance in low-flux coherent active imagery systems. We show that when photon noise is expected, the performance of classical detection techniques designed for pure and fully developed speckle images can be improved with no increase in algorithm complexity. Furthermore, the mean photon number under which photon noise becomes sensitive is higher when the target and background mean values are unknown than in the idealized case, where they are assumed to be known, and when the reflectivity ratio between the target and the background is low.

  11. Effects of low-frequency noise in driven coherent nanodevices

    NASA Astrophysics Data System (ADS)

    Falci, G.; Berritta, M.; Russo, A.; D'Arrigo, A.; Paladino, E.

    2012-11-01

    We study the effect of low-frequency noise in ac-driven two- or many-level coherent nanodevices. Fluctuations in the properties of the device are translated into equivalent fluctuations of the driving fields. The impact on Rabi oscillations can be modulated with the detuning and minimized at resonance. In three-level atoms slow noise produces qualitative changes for protocols as coherent population transfer. We propose a strategy allowing us to operate at parity symmetry points, where the device is well protected against noise, despite selection rules preventing direct couplings to external fields of involved transitions.

  12. Restoring fish ecological quality in estuaries: Implication of interactive and cumulative effects among anthropogenic stressors.

    PubMed

    Teichert, Nils; Borja, Angel; Chust, Guillem; Uriarte, Ainhize; Lepage, Mario

    2016-01-15

    Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. A Millennium of Anthropogenic Land Cover Change and its Effects on Climate

    NASA Astrophysics Data System (ADS)

    Pongratz, J.; Reick, C.; Raddatz, T.; Claussen, M.

    2007-12-01

    Anthropogenic climate change is generally thought to have begun with the industrial revolution, when humans started to considerably alter the composition of the atmosphere by emissions from fossil fuels. Human impact on the environment, however, started much earlier: Thousands of years ago, land was already transformed for use in agriculture and livestock farming. It is recognized that anthropogenic land cover change at today's scale has a significant impact on local to global climate. Yet, the effects of pre-industrial land use are not well understood. A main obstacle is the lack of quantitative data on historic land use activity prior to AD~1700 and a detailed analysis of its effects on the surface energy balance and the carbon cycle. This contribution presents advancements in both aspects. First, we present a simple method that consistently estimates the extent of crop and pasture areas for AD~800 to 1700 on a geographically explicit scale based on population data. Published land use data are used from AD~1700 until present. Uncertainties associated with data and method, including the effects of agrotechnical development, are assessed, and data sets of highest and lowest possible land use dynamics are provided. This land use reconstruction can be used to assess the human impact on the environment in pre-industrial times at high spatial and temporal resolution. It will be made freely available to the scientific community. The millennial land use reconstruction is then used in a complex climate model to quantify changes in radiative forcing. Results show that the energy balance was significantly influenced by human activity already in AD~800. Regional monthly means of radiative forcing reach up to 2.5~W/m2. Our results are in line with previous studies covering the recent centuries. The impact of pre-industrial land use change on the carbon balance is estimated using two independent approaches: a process-based soil and vegetation model, and a book-keeping model

  14. Effects of Meteorological Conditions on Reactions to Noise Exposure

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P. (Technical Monitor); Fields, James M.

    2004-01-01

    More than 80,000 residents' responses to transportation noise at different times of year provide the best, but imprecise, statistical estimates of the effects of season and meteorological conditions on community response to noise. Annoyance with noise is found to be slightly statistically significantly higher in the summer than in the winter in a seven-year study in the Netherlands. Analyses of 41 other surveys drawn from diverse countries, climates, and times of year find noise annoyance is increased by temperature, and may be increased by more sunshine, less precipitation, and reduced wind speeds. Meteorological conditions on the day of the interview or the immediately preceding days do not appear to have any more effect on reactions than do the conditions over the immediately preceding weeks or months.

  15. Effect of thermal noise on random lasers in diffusion regime

    NASA Astrophysics Data System (ADS)

    Zarei, Mohammad Ali; Hosseini-Farzad, Mahmood; Montakhab, Afshin

    2015-09-01

    In this paper, we study the effects of thermal noise on the time evolution of a weak light pulse (probe) in the presence of a strong light pulse (pump) within a gain medium which includes random scatterer particles. Suitable thermal noise term is added to a set of four coupled equations including three diffusion equations for energy densities and a rate equation for the upper level population in a four-level gain medium. These equations have been solved simultaneously by Crank-Nicholson numerical method. The main result is that the back-scattered output probe light is increased as the thermal noise strength is increased and simultaneously, with the same rate, the amplified spontaneous emission is decreased. Therefore, the amplified response of the random laser in diffusion regime for the input probe pulse is enhanced due to effect of the thermal noise.

  16. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California

    PubMed Central

    Batllori, Enric; Moritz, Max A.; Waller, Eric K.; Berck, Peter; Flint, Alan L.; Flint, Lorraine E.; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change. PMID:27124597

  17. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California.

    PubMed

    Mann, Michael L; Batllori, Enric; Moritz, Max A; Waller, Eric K; Berck, Peter; Flint, Alan L; Flint, Lorraine E; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state's fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change.

  18. Simulated high speed flight effects on supersonic jet noise

    NASA Astrophysics Data System (ADS)

    Norum, Thomas D.; Brown, Martha C.

    1993-10-01

    A free jet is utilized to investigate the changes in the noise received from supersonic jets in high speed subsonic flight. Flight Mach numbers to 0.9 are simulated for supersonic jets with fully expanded Mach numbers between 1 and 2. Plume pressure measurements show only minor changes in the shock structure of off-design jets up to a Mach number of 0.6. Correspondingly, far-field noise measurements indicate little change to the broadband shock noise emitted at right angles to the jet. However, measurements within the free jet show that convection effects on the noise are substantial, and that the point source convective amplification that is proportional to the fourth power of the Doppler factor may apply for broadband shock noise in flight. Measurements of jet mixing noise for an on-design supersonic jet show that the current predictions of mixing noise in flight can be extended to flight Mach numbers of at least 0.5.

  19. Noise exposure and auditory effects on preschool personnel.

    PubMed

    Sjödin, Fredrik; Kjellberg, Anders; Knutsson, Anders; Landström, Ulf; Lindberg, Lennart

    2012-01-01

    Hearing impairments and tinnitus are being reported in an increasing extent from employees in the preschool. The investigation included 101 employees at 17 preschools in Umeå county, Sweden. Individual noise recordings and stationary recordings in dining rooms and play halls were conducted at two departments per preschool. The effects of noise exposures were carried out through audiometric screenings and by use of questionnaires. The average individual noise exposure was close to 71 dB(A), with individual differences but small differences between the preschools. The noise levels in the dining room and playing halls were about 64 dB(A), with small differences between the investigated types of rooms and preschools. The hearing loss of the employees was significantly higher for the frequencies tested when compared with an unexposed control group in Sweden. Symptoms of tinnitus were reported among about 31% of the employees. Annoyance was rated as somewhat to very annoying. The voices of the children were the most annoying noise source. The dB(A) level and fluctuation of the noise exposure were significantly correlated to the number of children per department. The preschool sound environment is complex and our findings indicate that the sound environment is hazardous regarding auditory disorders. The fluctuation of the noise is of special interest for further research.

  20. Simulated high speed flight effects on supersonic jet noise

    NASA Technical Reports Server (NTRS)

    Norum, Thomas D.; Brown, Martha C.

    1993-01-01

    A free jet is utilized to investigate the changes in the noise received from supersonic jets in high speed subsonic flight. Flight Mach numbers to 0.9 are simulated for supersonic jets with fully expanded Mach numbers between 1 and 2. Plume pressure measurements show only minor changes in the shock structure of off-design jets up to a Mach number of 0.6. Correspondingly, far-field noise measurements indicate little change to the broadband shock noise emitted at right angles to the jet. However, measurements within the free jet show that convection effects on the noise are substantial, and that the point source convective amplification that is proportional to the fourth power of the Doppler factor may apply for broadband shock noise in flight. Measurements of jet mixing noise for an on-design supersonic jet show that the current predictions of mixing noise in flight can be extended to flight Mach numbers of at least 0.5.

  1. Multiple anthropogenic stressors exert complex, interactive effects on a coral reef community

    NASA Astrophysics Data System (ADS)

    Muthukrishnan, Ranjan; Fong, Peggy

    2014-12-01

    Multiple natural and anthropogenic stressors impact coral reefs across the globe leading to declines of coral populations, but the relative importance of different stressors and the ways they interact remain poorly understood. Because coral reefs exist in environments commonly impacted by multiple stressors simultaneously, understanding their interactions is of particular importance. To evaluate the role of multiple stressors we experimentally manipulated three stressors (herbivore abundance, nutrient supply, and sediment loading) in plots on a natural reef in the Gulf of Panamá in the Eastern Tropical Pacific. Monitoring of the benthic community (coral, macroalgae, algal turf, and crustose coralline algae) showed complex responses with all three stressors impacting the community, but at different times, in different combinations, and with varying effects on different community members. Reduction of top-down control in combination with sediment addition had the strongest effect on the community, and led to approximately three times greater algal biomass. Coral cover was reduced in all experimental units with a negative effect of nutrients over time and a synergistic interaction between herbivore exclosures and sediment addition. In contrast, nutrient and sediment additions interacted antagonistically in their impacts on crustose coralline algae and turf algae so that in combination the treatments limited each other's effects. Interactions between stressors and temporal variability indicated that, while each stressor had the potential to impact community structure, their combinations and the broader environmental conditions under which they acted strongly influenced their specific effects. Thus, it is critical to evaluate the effects of stressors on community dynamics not only independently but also under different combinations or environmental conditions to understand how those effects will be played out in more realistic scenarios.

  2. Neuropharmacological and cochleotoxic effects of styrene. Consequences on noise exposures.

    PubMed

    Campo, Pierre; Venet, Thomas; Thomas, Aurélie; Cour, Chantal; Brochard, Céline; Cosnier, Frédéric

    2014-01-01

    Occupational noise exposure can damage workers' hearing, particularly when combined with exposure to cochleotoxic chemicals such as styrene. Although styrene-induced cochlear impairments only become apparent after a long incubation period, the pharmacological impact of styrene on the central nervous system (CNS) can be rapidly measured by determining the threshold of the middle-ear acoustic reflex (MER) trigger. The aim of the study was to evaluate the effects of a noise (both continuous and impulse), and a low concentration of styrene [300ppm<(threshold limit value×10) safety factor] on the peripheral auditory receptor, and on the CNS in rats. The impact of the different conditions on hearing loss was assessed using distortion product oto-acoustic emissions, and histological analysis of cochleae. Although the LEX,8h (8-hour time-weighted average exposure) of the impulse noise was lower (80dB SPL sound pressure level) than that of the continuous noise (85dB SPL), it appeared more detrimental to the peripheral auditory receptors. A co-exposure to styrene and continuous noise was less damaging than exposure to continuous noise alone. In contrast, the traumatic effects of impulse noise on the organ of Corti were enhanced by co-exposure to styrene. The pharmacological effects of the solvent on the CNS were discussed to put forward a plausible explanation of these surprising results. We hypothesize that CNS effects of styrene may account for this apparent paradox. Based on the present results, the temporal structure of the noise should be reintroduced as a key parameter in hearing conservation regulations.

  3. Effect of external classroom noise on schoolchildren's reading and mathematics performance: correlation of noise levels and gender.

    PubMed

    Papanikolaou, M; Skenteris, N; Piperakis, S M

    2015-02-01

    The present study investigated the effect of low, medium, and high traffic road noise as well as irrelevant background speech noise on primary school children's reading and mathematical performance. A total of 676 participants (324 boys, 47.9% and 352 girls, 52.1%) of the 4th and 5th elementary classes participated in the project. The participants were enrolled in public primary schools from urban areas and had ages ranging from 9 to 10 years and from. Schools were selected on the basis of increasing levels of exposure to road traffic noise and then classified into three categories (Low noise: 55-66 dB, Medium noise: 67-77 dB, and High noise: 72-80 dB). We measured reading comprehension and mathematical skills in accordance with the national guidelines for elementary education, using a test designed specifically for the purpose of this study. On the one hand, children in low-level noise schools showed statistically significant differences from children in medium- and high-level noise schools in reading performance (p<0.001). On the other hand, children in low-level noise schools differed significantly from children in high-level noise schools but only in mathematics performance (p=0.001). Girls in general did better in reading score than boys, especially in schools with medium- and high-level noise. Finally the levels of noise and gender were found to be two independent factors.

  4. A Minimal Invasive Method to Forecast the Effects of Anthropogenic Disturbance on Tropical Cave Beetle Communities.

    PubMed

    Cajaiba, R L; Cabral, J A; Santos, M

    2016-04-01

    Many tropical landscapes are changing rapidly, with uncertain outcomes for biodiversity, landscape function, and the corresponding landscape services. Therefore, monitoring and adaptively managing the drivers and consequences of landscape change while sustaining the production of essential resources have become research and policy priorities. In this perspective, we have applied a recent framework, the stochastic dynamic methodology (StDM), with the purpose of understanding the effects of natural and anthropogenic disturbances on caves' integrity using cave beetle communities (Coleoptera) as ecological indicators. The proposed method was preceeded by a generalized linear model for discriminating significant relationships between the selected indicators, the structural changes in the caves, and the epigean habitats associated. The obtained results showed different ecological trends in response to the environmental changes. Overall, the simulation results seem to demonstrate the StDM reliability in determining the effects of habitat dynamics, that is, the expansion of agricultural activities, in areas near the caves in the structure of cave beetle communities. The applied method, based on universal information-theoretic principles, can be easily implemented and interpreted by environmental managers and decision makers, enabling anticipating impacts and supporting the development of measures aimed at minimizing the identified problems.

  5. How well do ecosystem indicators communicate the effects of anthropogenic eutrophication?

    NASA Astrophysics Data System (ADS)

    McQuatters-Gollop, Abigail; Gilbert, Alison J.; Mee, Laurence D.; Vermaat, Jan E.; Artioli, Yuri; Humborg, Christoph; Wulff, Fred

    2009-05-01

    Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European assessment of eutrophication symptoms. Here we summarize responses to nutrient enrichment in Europe's seas, comparing existing time-series of selected pelagic (phytoplankton biomass and community composition, turbidity, N:P ratio) and benthic (macro flora and faunal communities, bottom oxygen condition) indicators based on their effectiveness in assessing eutrophication effects. Our results suggest that the Black Sea and Northern Adriatic appear to be recovering from eutrophication due to economic reorganization in the Black Sea catchment and nutrient abatement measures in the case of the Northern Adriatic. The Baltic is most strongly impacted by eutrophication due to its limited exchange and the prevalence of nutrient recycling. Eutrophication in the North Sea is primarily a coastal problem, but may be exacerbated by climatic changes. Indicator interpretation is strongly dependent on sea-specific knowledge of ecosystem characteristics, and no single indicator can be employed to adequately compare eutrophication state between European seas. Communicating eutrophication-related information to policy-makers could be facilitated through the use of consistent indicator selection and monitoring methodologies across European seas. This work is discussed in the context of the European Commission's recently published Marine Strategy Directive.

  6. Modeling Study of the Effect of Anthropogenic Aerosols on Late Spring Drought in South China

    SciTech Connect

    Hu, Ning; Liu, Xiaohong

    2013-10-01

    In this study, the mechanisms underlying the decadal variability of late spring precipitation in south China are investigated using the latest version 1 of Community Earth System Model (CESM1). We aim to unravel the effects of different climate forcing agents, such as aerosols and greenhouse gases (GHGs), on the decadal variation of precipitation with transient experiments from pre-industry (for year 1850) to present-day (for year 2000). Our results reveal that: (1) CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in south China; (2) Only simulations including the forcing of anthropogenic aerosols can reproduce the observed decreasing trend of late spring precipitation from 1950-2000 in south China; (3) Aerosols affect the decadal change of precipitation mainly by altering the large scale atmospheric circulation, and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and (4) In comparison, other climate forcing agents, such as GHGs, have much smaller effects on the decadal change of spring precipitation in south China. Key words: precipitation, aerosols, climate change, south China, Community Earth System Model

  7. Effects of Bifurcations on Aft-Fan Engine Nacelle Noise

    NASA Technical Reports Server (NTRS)

    Nark, Douglas M.; Farassat, Fereidoun; Pope, D. Stuart; Vatsa, Veer N.

    2004-01-01

    Aft-fan engine nacelle noise is a significant factor in the increasingly important issue of aircraft community noise. The ability to predict such noise within complex duct geometries is a valuable tool in studying possible noise attenuation methods. A recent example of code development for such predictions is the ducted fan noise propagation and radiation code CDUCT-LaRC. This work focuses on predicting the effects of geometry changes (i.e. bifurcations, pylons) on aft fan noise propagation. Beginning with simplified geometries, calculations show that bifurcations lead to scattering of acoustic energy into higher order modes. In addition, when circumferential mode number and the number of bifurcations are properly commensurate, bifurcations increase the relative importance of the plane wave mode near the exhaust plane of the bypass duct. This is particularly evident when the bypass duct surfaces include acoustic treatment. Calculations involving more complex geometries further illustrate that bifurcations and pylons clearly affect modal content, in both propagation and radiation calculations. Additionally, results show that consideration of acoustic radiation results may provide further insight into acoustic treatment effectiveness for situations in which modal decomposition may not be straightforward. The ability of CDUCT-LaRC to handle complex (non-axisymmetric) multi-block geometries, as well as axially and circumferentially segmented liners, allows investigation into the effects of geometric elements (bifurcations, pylons).

  8. Wind noise in hearing aids: I. Effect of wide dynamic range compression and modulation-based noise reduction.

    PubMed

    Chung, King

    2012-01-01

    The objectives of this study were: (1) to examine the effect of wide dynamic range compression (WDRC) and modulation-based noise reduction (NR) algorithms on wind noise levels at the hearing aid output; and (2) to derive effective strategies for clinicians and engineers to reduce wind noise in hearing aids. Three digital hearing aids were fitted to KEMAR. The noise output was recorded at flow velocities of 0, 4.5, 9.0, and 13.5 m/s in a wind tunnel as the KEMAR head was turned from 0° to 360°. Flow noise levels were compared between the 1:1 linear and 3:1 WDRC conditions, and between NR-activated and NR-deactivated conditions when the hearing aid was programmed to the directional and omnidirectional modes. The results showed that: (1) WDRC increased low-level noise and reduced high-level noise; and (2) different noise reduction algorithms provided different amounts of wind noise reduction in different microphone modes, frequency regions, flow velocities, and head angles. Wind noise can be reduced by decreasing the gain for low-level inputs, increasing the compression ratio for high-level inputs, and activating modulation-based noise reduction algorithms.

  9. Internal additive noise effects in stochastic resonance using organic field effect transistor

    SciTech Connect

    Suzuki, Yoshiharu; Asakawa, Naoki; Matsubara, Kiyohiko

    2016-08-29

    Stochastic resonance phenomenon was observed in organic field effect transistor using poly(3-hexylthiophene), which enhances performance of signal transmission with application of noise. The enhancement of correlation coefficient between the input and output signals was low, and the variation of correlation coefficient was not remarkable with respect to the intensity of external noise, which was due to the existence of internal additive noise following the nonlinear threshold response. In other words, internal additive noise plays a positive role on the capability of approximately constant signal transmission regardless of noise intensity, which can be said “homeostatic” behavior or “noise robustness” against external noise. Furthermore, internal additive noise causes emergence of the stochastic resonance effect even on the threshold unit without internal additive noise on which the correlation coefficient usually decreases monotonically.

  10. Effect of turbine dental drill noise on dentists' hearing.

    PubMed

    Man, A; Neuman, H; Assif, D

    1982-04-01

    The effect of high-speed dental turbines on dentists' hearing was investigated. The two types of dental turbines used most commonly in the Tel Aviv area and their average time of daily use were established by means of questionnaires. The noise pressure level of these turbines at a distance of 30.0 cm was measured. Twenty subjects were exposed to the turbine noise for a period equal to the average time of the drill's daily use. The noise pressure levels of the turbines were found to be nonhazardous by the accepted damage-risk criteria. The temporary threshold shifts of the subjects exposed were nil or insignificant. It was concluded that the risk of damage to the dentist's hearing due to dental turbine noise in the normal course of a working day is slight.

  11. Effects of fast presynaptic noise in attractor neural networks.

    PubMed

    Cortes, J M; Torres, J J; Marro, J; Garrido, P L; Kappen, H J

    2006-03-01

    We study both analytically and numerically the effect of presynaptic noise on the transmission of information in attractor neural networks. The noise occurs on a very short timescale compared to that for the neuron dynamics and it produces short-time synaptic depression. This is inspired in recent neurobiological findings that show that synaptic strength may either increase or decrease on a short timescale depending on presynaptic activity. We thus describe a mechanism by which fast presynaptic noise enhances the neural network sensitivity to an external stimulus. The reason is that, in general, presynaptic noise induces nonequilibrium behavior and, consequently, the space of fixed points is qualitatively modified in such a way that the system can easily escape from the attractor. As a result, the model shows, in addition to pattern recognition, class identification and categorization, which may be relevant to the understanding of some of the brain complex tasks.

  12. Effects of anthropogenic heat release upon the urban climate in a Japanese megacity.

    PubMed

    Narumi, Daisuke; Kondo, Akira; Shimoda, Yoshiyuki

    2009-05-01

    This report presents results of investigations of the influence of anthropogenic heat release in Japanese megacity (Keihanshin district) upon the urban climate, using the energy database [Shimoda et al., 1999. Estimation and evaluation of artificial waste heat in urban area. Selected Papers from the Conference ICB-ICUC'99 WCASP-50 WMO/TD no. 1026] as a part of the land-surface boundary conditions of a mesoscale meteorological simulation model. The calculated results related to atmospheric temperature distribution were similar to observed values not only for daily averages but also for amplitudes and phases of diurnal change. To reproduce accurately, it is essential to reproduce urban characteristics such as an urban canopy and anthropogenic heat release in a fine resolution mesh. We attempted an analysis using current data for anthropogenic heat and under uniform heat release conditions, to investigate temporal and spatial characteristics in relation to the influence of anthropogenic heat release on the urban climate. The results of investigation into the influence of anthropogenic heat release on atmospheric temperature using current data indicate that the amount of heat released is lower at night than during the day, but the temperature rise is nearly 3 times greater. Results of investigation into the influence of anthropogenic heat release on wind systems using current data indicate that the onset of land breezes is delayed, particularly in a coastal area. Investigation into the temporal characteristics related to the influence of anthropogenic heat release under uniform heat release conditions showed a maximum influence on temperature during the predawn period.

  13. Influence of background noise on the performance in the odor sensitivity task: effects of noise type and extraversion.

    PubMed

    Seo, Han-Seok; Hähner, Antje; Gudziol, Volker; Scheibe, Mandy; Hummel, Thomas

    2012-10-01

    Recent research demonstrated that background noise relative to silence impaired subjects' performance in a cognitively driven odor discrimination test. The current study aimed to investigate whether the background noise can also modulate performance in an odor sensitivity task that is less cognitively loaded. Previous studies have shown that the effect of background noise on task performance can be different in relation to degree of extraversion and/or type of noise. Accordingly, we wanted to examine whether the influence of background noise on the odor sensitivity task can be altered as a function of the type of background noise (i.e., nonverbal vs. verbal noise) and the degree of extraversion (i.e., introvert vs. extrovert group). Subjects were asked to conduct an odor sensitivity task in the presence of either nonverbal noise (e.g., party sound) or verbal noise (e.g., audio book), or silence. Overall, the subjects' mean performance in the odor sensitivity task was not significantly different across three auditory conditions. However, with regard to the odor sensitivity task, a significant interaction emerged between the type of background noise and the degree of extraversion. Specifically, verbal noise relative to silence significantly impaired or improved the performance of the odor sensitivity task in the introvert or extrovert group, respectively; the differential effect of introversion/extraversion was not observed in the nonverbal noise-induced task performance. In conclusion, our findings provide new empirical evidence that type of background noise and degree of extraversion play an important role in modulating the effect of background noise on subjects' performance in an odor sensitivity task.

  14. Increasing CO2 Coupled with Other Anthropogenic Perturbations: Effects on Ozone and Other Trace Gases

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Douglass, A. R.

    1999-01-01

    The GSFC 2D interactive chemistry-radiation-dynamics model has been used to study the effects on stratospheric trace gases of past and future CO2 increases coupled with changes in CFC'S, methane, and nitrous oxide. Previous simulations with the GSFC model showed that the stratospheric cooling calculated to result from doubling atmospheric CO2 would lead, in the absence of a growth of other anthropogenic gases, to a decrease in upper stratospheric NO(y) of roughly 15%. This work has been extended to simulate changes in stratospheric chemistry and dynamics occurring between the years 1960 and 2050. The simulations have been carried out with and without changes in CO2. In the low latitude upper stratosphere ozone is predicted to be 10% greater in 2050 than in 1990 when increased CO2 is included, compared with an increase of only 2% without the inclusion of CO2. In the low latitude lower stratosphere, ozone is predicted to decrease by about 1% between 1990 and 2050 when CO2 changes are taken into account, in contrast to an approximate 3% increase when they are not. The simulated behavior of water vapor is another example of the coupled responses. Between 1990 and 2050 low latitude water vapor is predicted to increase by 4% and 2% in the upper and lower stratosphere, respectively, without the inclusion of CO2 increases. with the inclusion of CO2 changes, the water vapor increases are predicted to be roughly 12% and 8%, for the upper and lower stratosphere, respectively.

  15. Effects of anthropogenic salinization on biological traits and community composition of stream macroinvertebrates.

    PubMed

    Szöcs, Eduard; Coring, Eckhard; Bäthe, Jürgen; Schäfer, Ralf B

    2014-01-15

    Salinization of rivers resulting from industrial discharge or road-deicing can adversely affect macroinvertebrates. Trait-based approaches are a promising tool in ecological monitoring and may perform better than taxonomy-based approaches. However only little is known how and which biological traits are affected by salinization. We investigated the effects of anthropogenic salinization on macroinvertebrate communities and biological traits in the Werra River, Germany and compared the taxonomic and trait response. We found a change in macroinvertebrate community and trait composition. Communities at saline sites were characterized by the three exotic species Gammarus tigrinus, Apocorophium lacustre and Potamopyrgus antipodarum. The frequencies of trait modalities long life cycle duration, respiration by gill, ovoviviparity, shredder and multivoltinism were statistically significantly increased at saline sites. The trait-based ordination resulted in a higher explained variance than the taxonomy-based ordination, indicating a better performance of the trait-based approach, resulting in a better discrimination between saline and non-saline sites. Our results are in general agreement with other studies from Europe, indicating a trait convergence for saline streams, being dominated by the traits ovoviviparity and multivoltinism. Three further traits (respiration by gill, life cycle duration and shredders) responded strongly to salinization, but this may primarily be attributed to the dominance of a single invasive species, G. tigrinus, at the saline sites in the Werra River.

  16. Effects of Spectral Shifting on Speech Perception in Noise

    PubMed Central

    Li, Tianhao; Fu, Qian-Jie

    2010-01-01

    The present study used eight normal-hearing (NH) subjects, listening to acoustic cochlear implant (CI) simulations, to examine the effects of spectral shifting on speech recognition in noise. Speech recognition was measured using spectrally matched and shifted speech (vowels, consonants, and IEEE sentences), generated by 8-channel, sine-wave vocoder. Measurements were made in quiet and in noise (speech-shaped static noise and speech-babble at 5 dB signal-to-noise ratio). One spectral match condition and four spectral shift conditions were investigated: 2 mm, 3 mm, and 4 mm linear shift, and 3 mm shift with compression, in terms of cochlear distance. Results showed that speech recognition scores dropped because of noise and spectral shifting, and that the interactive effects of spectral shifting and background conditions depended on the degree/type of spectral shift, background conditions, and the speech test materials. There was no significant interaction between spectral shifting and two noise conditions for all speech test materials. However, significant interactions between linear spectral shifts and all background conditions were found in sentence recognition; significant interactions between spectral shift types and all background conditions were found in vowel recognition. Overall, the results suggest that tonotopic mismatch may affect performance of CI users in complex listening environments. PMID:20868733

  17. Characterization of the noise effect on weak synchronization.

    PubMed

    Kim, Sang-Yoon; Lim, Woochang; Jalnine, Alexei; Kuznetsov, Sergey P

    2003-01-01

    We investigate the noise effect on weak synchronization in two coupled identical one-dimensional (1D) maps. Due to the existence of positive local transverse Lyapunov exponents, the weakly stable synchronous chaotic attractor (SCA) becomes sensitive with respect to the variation of noise intensity. To quantitatively characterize such noise sensitivity, we introduce a quantifier, called the noise sensitivity exponent (NSE). For the case of bounded noise, the values of the NSE are found to be the same as those of the exponent characterizing a parameter sensitivity of the weakly stable SCA in presence of a parameter mismatch between the two 1D maps. Furthermore, it is found that the scaling exponent for the average time spent near the diagonal for both the bubbling and riddling cases occurring in the regime of weak synchronization is given by the reciprocal of the NSE, as in the parameter-mismatching case. Consequently, both the noise and parameter mismatch have the same effect on the scaling behavior of the average characteristic time.

  18. Effects of spectral shifting on speech perception in noise.

    PubMed

    Li, Tianhao; Fu, Qian-Jie

    2010-12-01

    The present study used eight normal-hearing (NH) subjects, listening to acoustic cochlear implant (CI) simulations, to examine the effects of spectral shifting on speech recognition in noise. Speech recognition was measured using spectrally matched and shifted speech (vowels, consonants, and IEEE sentences), generated by 8-channel, sine-wave vocoder. Measurements were made in quiet and in noise (speech-shaped static noise and speech-babble at 5 dB signal-to-noise ratio). One spectral match condition and four spectral shift conditions were investigated: 2 mm, 3 mm, and 4 mm linear shift, and 3 mm shift with compression, in terms of cochlear distance. Results showed that speech recognition scores dropped because of noise and spectral shifting, and that the interactive effects of spectral shifting and background conditions depended on the degree/type of spectral shift, background conditions, and the speech test materials. There was no significant interaction between spectral shifting and two noise conditions for all speech test materials. However, significant interactions between linear spectral shifts and all background conditions were found in sentence recognition; significant interactions between spectral shift types and all background conditions were found in vowel recognition. Overall, the results suggest that tonotopic mismatch may affect performance of CI users in complex listening environments. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. An effective method for computing the noise in biochemical networks

    PubMed Central

    Zhang, Jiajun; Nie, Qing; He, Miao; Zhou, Tianshou

    2013-01-01

    We present a simple yet effective method, which is based on power series expansion, for computing exact binomial moments that can be in turn used to compute steady-state probability distributions as well as the noise in linear or nonlinear biochemical reaction networks. When the method is applied to representative reaction networks such as the ON-OFF models of gene expression, gene models of promoter progression, gene auto-regulatory models, and common signaling motifs, the exact formulae for computing the intensities of noise in the species of interest or steady-state distributions are analytically given. Interestingly, we find that positive (negative) feedback does not enlarge (reduce) noise as claimed in previous works but has a counter-intuitive effect and that the multi-OFF (or ON) mechanism always attenuates the noise in contrast to the common ON-OFF mechanism and can modulate the noise to the lowest level independently of the mRNA mean. Except for its power in deriving analytical expressions for distributions and noise, our method is programmable and has apparent advantages in reducing computational cost. PMID:23464139

  20. The Anthropogenic/Lightning Effects Around Houston: The Houston Environmental Aerosol Thunderstorm (HEAT) Project - 2005

    NASA Astrophysics Data System (ADS)

    Orville, R. E.

    2004-12-01

    A major field program will occur in summer 2005 to determine the sources and causes for the enhanced cloud-to-ground lightning over Houston, Texas. This program will be in association with simultaneous experiments supported by the Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ), formally the Texas Natural Resource Conservation Commission (TNRCC). Recent studies covering the period 1989-2002 document a 60 percent increase of cloud-to-ground lightning in the Houston area as compared to surrounding background values, which is second in flash density only to the Tampa Bay, Florida area. We suggest that the elevated flash densities could result from several factors, including 1) the convergence due to the urban heat island effect and complex sea breeze (thermal hypothesis), and 2) the increasing levels of air pollution from anthropogenic sources producing numerous small cloud droplets and thereby suppressing mean droplet size (aerosol hypothesis). The latter effect would enable more cloud water to reach the mixed phase region where it is involved in the formation of precipitation and the separation of electric charge, leading to an enhancement of lightning. The primary goals of HEAT are to examine the effects of (1) pollution, (2) the urban heat island, and (3) the complex coastline on storms and lightning characteristics in the Houston area. The transport of air pollutants by Houston thunderstorms will be investigated. In particular, the relative amounts of lightning-produced and convectively transported NOx into the upper troposphere will be determined, and a comparison of the different NOx sources in the urban area of Houston will be developed. The HEAT project is based on the observation that there is an enhancement in cloud-to-ground (CG) lightning. Total lightning (intracloud (IC) and CG) will be measured using a lightning mapping system (LDAR II) to observe if there is an enhancement in intracloud lightning as well.

  1. The Anthropogenic Effects of Hydrocarbon Inputs to Coastal Seas: Are There Potential Biogeochemical Impacts?

    NASA Astrophysics Data System (ADS)

    Anderson, M. R.; Rivkin, R. B.

    2016-02-01

    Petroleum hydrocarbon discharges related to fossil fuel exploitation have the potential to alter microbial processes in the upper ocean. While the ecotoxicological effects of such inputs are commonly evaluated, the potential for eutrophication from the constituent organic and inorganic nutrients has been largely ignored. Hydrocarbons from natural seeps and anthropogenic sources represent a measurable source of organic carbon for surface waters. The most recent (1989-1997) estimate of average world-wide input of hydrocarbons to the sea is 1.250 x 1012 g/yr ≈ 1.0 x 1012g C/year. Produced water from offshore platforms is the largest waste stream from oil and gas exploitation and contributes significant quantities of inorganic nutrients such as N, P and Fe. In coastal areas where such inputs are a significant source of these nutrients, model studies show the potential to shift production toward smaller cells and net heterotrophy. The consequences of these nutrient sources for coastal systems and semi enclosed seas are complex and difficult to predict, because (1) there is a lack of comprehensive data on inputs and in situ concentrations and (2) the is no conceptual or quantitative framework to consider their effects on ocean biogeochemical processes. Here we use examples from the North Sea (produced water discharges 1% total riverine input and NH4 3% of the annual riverine nitrogen load), the South China Sea (total petroleum hydrocarbons = 10-1750 μg/l in offshore waters), and the Gulf of Mexico (seeps = 76-106 x 109 gC/yr, Macondo blowout 545 x 109 gC) to demonstrate how hydrocarbon and produced water inputs can influence basin scale biogeochemical and ecosystem processes and to propose a framework to consider these effects on larger scales.

  2. Power Laws, Flicker Noise, and the Barkhausen Effect

    DTIC Science & Technology

    1993-10-01

    AD-A274 702 AD TECHNICAL REPORT ARCCB-TR-93038 POWER LAWS, FLICKER NOISE, AND THE BARKHAUSEN EFFECT DTIC ELECTE JA~N 211994 3 L.V. MEISEL S D P.J...CATES C&MORD October 1993 Fuel 4. TITLE AND SUBTITU S. FUNDING NUMBERS POWER LAWS. FUCKER NOISE. AND THE BARKHAUSEN EFFECT AMCMS: 611L02.H61L1 6. AUTHOR... Barkhausen effect was studied in three ferromagnetic metals: an amorphous alloy, iron. and alumel. The data exhibit all the characteristics of self

  3. Effect of Dust and Anthropogenic Aerosols on Columnar Aerosol Optical Properties over Darjeeling (2200 m asl), Eastern Himalayas, India

    PubMed Central

    Chatterjee, Abhijit; Ghosh, Sanjay K.; Adak, Anandamay; Singh, Ajay K.; Devara, Panuganti C. S.; Raha, Sibaji

    2012-01-01

    Background The loading of atmospheric particulate matter (aerosol) in the eastern Himalaya is mainly regulated by the locally generated anthropogenic aerosols from the biomass burning and by the aerosols transported from the distance sources. These different types of aerosol loading not only affect the aerosol chemistry but also produce consequent signature on the radiative properties of aerosol. Methodology/Principal Findings An extensive study has been made to study the seasonal variations in aerosol components of fine and coarse mode aerosols and black carbon along with the simultaneous measurements of aerosol optical depth on clear sky days over Darjeeling, a high altitude station (2200 masl) at eastern Himalayas during the year 2008. We observed a heavy loading of fine mode dust component (Ca2+) during pre-monsoon (Apr – May) which was higher by 162% than its annual mean whereas during winter (Dec – Feb), the loading of anthropogenic aerosol components mainly from biomass burning (fine mode SO42− and black carbon) were higher (76% for black carbon and 96% for fine mode SO42−) from their annual means. These high increases in dust aerosols during pre-monsoon and anthropogenic aerosols during winter enhanced the aerosol optical depth by 25 and 40%, respectively. We observed that for every 1% increase in anthropogenic aerosols, AOD increased by 0.55% during winter whereas for every 1% increase in dust aerosols, AOD increased by 0.46% during pre-monsoon. Conclusion/Significance The natural dust transport process (during pre-monsoon) plays as important a role in the radiation effects as the anthropogenic biomass burning (during winter) and their differential effects (rate of increase of the AOD with that of the aerosol concentration) are also very similar. This should be taken into account in proper modeling of the atmospheric environment over eastern Himalayas. PMID:22792264

  4. Effect of dust and anthropogenic aerosols on columnar aerosol optical properties over Darjeeling (2200 m asl), eastern Himalayas, India.

    PubMed

    Chatterjee, Abhijit; Ghosh, Sanjay K; Adak, Anandamay; Singh, Ajay K; Devara, Panuganti C S; Raha, Sibaji

    2012-01-01

    The loading of atmospheric particulate matter (aerosol) in the eastern Himalaya is mainly regulated by the locally generated anthropogenic aerosols from the biomass burning and by the aerosols transported from the distance sources. These different types of aerosol loading not only affect the aerosol chemistry but also produce consequent signature on the radiative properties of aerosol. An extensive study has been made to study the seasonal variations in aerosol components of fine and coarse mode aerosols and black carbon along with the simultaneous measurements of aerosol optical depth on clear sky days over Darjeeling, a high altitude station (2200 masl) at eastern Himalayas during the year 2008. We observed a heavy loading of fine mode dust component (Ca(2+)) during pre-monsoon (Apr-May) which was higher by 162% than its annual mean whereas during winter (Dec-Feb), the loading of anthropogenic aerosol components mainly from biomass burning (fine mode SO(4)(2-) and black carbon) were higher (76% for black carbon and 96% for fine mode SO(4)(2-)) from their annual means. These high increases in dust aerosols during pre-monsoon and anthropogenic aerosols during winter enhanced the aerosol optical depth by 25 and 40%, respectively. We observed that for every 1% increase in anthropogenic aerosols, AOD increased by 0.55% during winter whereas for every 1% increase in dust aerosols, AOD increased by 0.46% during pre-monsoon. The natural dust transport process (during pre-monsoon) plays as important a role in the radiation effects as the anthropogenic biomass burning (during winter) and their differential effects (rate of increase of the AOD with that of the aerosol concentration) are also very similar. This should be taken into account in proper modeling of the atmospheric environment over eastern Himalayas.

  5. Initial Integration of Noise Prediction Tools for Acoustic Scattering Effects

    NASA Technical Reports Server (NTRS)

    Nark, Douglas M.; Burley, Casey L.; Tinetti, Ana; Rawls, John W.

    2008-01-01

    This effort provides an initial glimpse at NASA capabilities available in predicting the scattering of fan noise from a non-conventional aircraft configuration. The Aircraft NOise Prediction Program, Fast Scattering Code, and the Rotorcraft Noise Model were coupled to provide increased fidelity models of scattering effects on engine fan noise sources. The integration of these codes led to the identification of several keys issues entailed in applying such multi-fidelity approaches. In particular, for prediction at noise certification points, the inclusion of distributed sources leads to complications with the source semi-sphere approach. Computational resource requirements limit the use of the higher fidelity scattering code to predict radiated sound pressure levels for full scale configurations at relevant frequencies. And, the ability to more accurately represent complex shielding surfaces in current lower fidelity models is necessary for general application to scattering predictions. This initial step in determining the potential benefits/costs of these new methods over the existing capabilities illustrates a number of the issues that must be addressed in the development of next generation aircraft system noise prediction tools.

  6. Effect of calcium channel noise in astrocytes on neuronal transmission

    NASA Astrophysics Data System (ADS)

    Tang, Jun; Liu, Tong-Bo; Ma, Jun; Luo, Jin-Ming; Yang, Xian-Qing

    2016-03-01

    In this study, a Langevin model is constructed by modifying a neuron-astrocyte coupled model that comprises a pyramidal neuron, an interneuron, and an astrocyte. This Langevin model considers random open-close transitions of calcium ion channels in the endoplasmic reticulum membrane of astrocytes. The effect of noise in the astrocytes on neuronal transmission is investigated numerically based on a random model under both normal and overexpression conditions of metabotropic glutamate receptors on astrocyte membranes. This study suggests that noise could change the firing patterns of two neurons during neuronal information transmission. Noise facilitates the occurrence of episodic spikes (ESs) in both neurons. However, the noise-induced ESs occur irregularly, compared with ESs in a deterministic model, and the change in regularity with noise exhibits the coherence- resonance phenomenon. Furthermore, synchronicity between noisy ESs in two neurons depends significantly on various parameters. ESs completely occur synchronously but irregularly in certain parameter regions, whereas ESs in other parameter values are antiphase synchronous. This study implies not only that the calcium dynamics in astrocytes could participate in neuronal transmission, but also that noise in astrocytes may be transferred to neurons and may affect synaptic transmission significantly.

  7. Effects of noise on speech production: Acoustic and perceptual analyses

    PubMed Central

    Van Summers, W.; Pisoni, David B.; Bernacki, Robert H.; Pedlow, Robert I.; Stokes, Michael A.

    2012-01-01

    Acoustical analyses were carried out on a set of utterances produced by two male speakers talking in quiet and in 80, 90, and 100 dB SPL of masking noise. In addition to replicating previous studies demonstrating increases in amplitude, duration, and vocal pitch while talking in noise, these analyses also found reliable differences in the formant frequencies and short-term spectra of vowels. Perceptual experiments were also conducted to assess the intelligibility of utterances produced in quiet and in noise when they were presented at equal S/N ratios for identification. In each experiment, utterances originally produced in noise were found to be more intelligible than utterances produced in the quiet. The results of the acoustic analyses showed clear and consistent differences in the acoustic–phonetic characteristics of speech produced in quiet versus noisy environments. Moreover, these acoustic differences produced reliable effects on intelligibility. The findings are discussed in terms of: (1) the nature of the acoustic changes that take place when speakers produce speech under adverse conditions such as noise, psychological stress, or high cognitive load; (2) the role of training and feedback in controlling and modifying a talker’s speech to improve performance of current speech recognizers; and (3) the development of robust algorithms for recognition of speech in noise. PMID:3183209

  8. Stress effects of noise in a field experiment in comparison to reactions to short term noise exposure in the laboratory.

    PubMed

    Ising, H; Michalak, R

    2004-01-01

    Reactions to noise-induced communication disturbance of 42 men during a seminar were investigated. Stress reactions with or without road traffic noise (Lm = 60 dBA) were compared. Traffic noise was played back via loudspeakers during one day in the seminar room. The following parameters were measured: Fatigue and mental tension by questionnaire; blood pressure and heart rate; excretion of adrenaline, noradrenaline and cAMP from the collected urine. The same subjects participated in a laboratory test where the blood pressure was measured during 5 minutes of rest and after 5 minutes of exposure to intermittent white noise (Lm=97 dBA). It was found that the noise in the field experiment caused psychological and physiological stress effects in half of the subjects. Increased mental tension was correlated to increases as well as decreases of the blood pressure. Systolic blood pressure reactions were stronger than the reactions of diastolic blood pressure. Noise sensitive subjects reacted stronger than the others. In the short-term laboratory test, systolic blood pressure increases were smaller than the diastolic increases. At the end of the 5 minutes noise exposure only the diastolic blood pressure increases were significant. There was no correlation between the blood pressure reactions in the two different noise exposure experiments. There existed a positive correlation between noise sensitivity and the systolic blood pressure increases during the seminar, whilst the correlation, between noise sensitivity and systolic blood pressure increases in the laboratory exposure, was negative. From these results we conclude that short-term noise exposure experiments do not provide information about the effects of long-term real life exposure to environmental noise. Potential health effects of chronic noise-induced disturbances of activities are discussed.

  9. Cardiovascular effects of environmental noise: research in Austria.

    PubMed

    Lercher, Peter; Botteldooren, Dick; Widmann, Ulrich; Uhrner, Ulrich; Kammeringer, Ewald

    2011-01-01

    Cardiovascular effects of noise rank second in terms of disability-adjusted life year (DALYs) after annoyance. Although research during the past decade has consolidated the available data base, the most recent meta-analysis still shows wide confidence intervals - indicating imprecise information for public health risk assessment. The alpine area of Tyrol in the Austrian part of the Alps has experienced a massive increase in car and heavy goods traffic (road and rail) during the last 35 years. Over the past 25 years small-, middle-, and large-sized epidemiological health surveys have been conducted - mostly within the framework of environmental health impact assessments. By design, these studies have emphasized a contextually driven environmental stress perspective, where the adverse health effects on account of noise are studied in a broader framework of environmental health, susceptibility, and coping. Furthermore, innovative exposure assessment strategies have been implemented. This article reviews the existing knowledge from these studies over time, and presents the exposure-response curves, with and without interaction assessment, based on standardized re-analyses and discusses it in the light of past and current cardiovascular noise effects research. The findings support relevant moderation by age, gender, and family history in nearly all studies and suggest a strong need for consideration of non-linearity in the exposure-response analyses. On the other hand, air pollution has not played a relevant role as a moderator in the noise-hypertension or the noise-angina pectoris relationship. Finally, different noise modeling procedures can introduce variations in the exposure response curves, with substantive consequences for public health risk assessment of noise exposure.

  10. Noise Reduction Effect of Multiple-Sampling-Based Signal-Readout Circuits for Ultra-Low Noise CMOS Image Sensors

    PubMed Central

    Kawahito, Shoji; Seo, Min-Woong

    2016-01-01

    This paper discusses the noise reduction effect of multiple-sampling-based signal readout circuits for implementing ultra-low-noise image sensors. The correlated multiple sampling (CMS) technique has recently become an important technology for high-gain column readout circuits in low-noise CMOS image sensors (CISs). This paper reveals how the column CMS circuits, together with a pixel having a high-conversion-gain charge detector and low-noise transistor, realizes deep sub-electron read noise levels based on the analysis of noise components in the signal readout chain from a pixel to the column analog-to-digital converter (ADC). The noise measurement results of experimental CISs are compared with the noise analysis and the effect of noise reduction to the sampling number is discussed at the deep sub-electron level. Images taken with three CMS gains of two, 16, and 128 show distinct advantage of image contrast for the gain of 128 (noise(median): 0.29 e−rms) when compared with the CMS gain of two (2.4 e−rms), or 16 (1.1 e−rms). PMID:27827972

  11. Noise Reduction Effect of Multiple-Sampling-Based Signal-Readout Circuits for Ultra-Low Noise CMOS Image Sensors.

    PubMed

    Kawahito, Shoji; Seo, Min-Woong

    2016-11-06

    This paper discusses the noise reduction effect of multiple-sampling-based signal readout circuits for implementing ultra-low-noise image sensors. The correlated multiple sampling (CMS) technique has recently become an important technology for high-gain column readout circuits in low-noise CMOS image sensors (CISs). This paper reveals how the column CMS circuits, together with a pixel having a high-conversion-gain charge detector and low-noise transistor, realizes deep sub-electron read noise levels based on the analysis of noise components in the signal readout chain from a pixel to the column analog-to-digital converter (ADC). The noise measurement results of experimental CISs are compared with the noise analysis and the effect of noise reduction to the sampling number is discussed at the deep sub-electron level. Images taken with three CMS gains of two, 16, and 128 show distinct advantage of image contrast for the gain of 128 (noise(median): 0.29 e(-)rms) when compared with the CMS gain of two (2.4 e(-)rms), or 16 (1.1 e(-)rms).

  12. Application of the anthropogenic allee effect model to trophy hunting as a conservation tool.

    PubMed

    Harris, Richard B; Cooney, Rosie; Leader-Williams, Nigel

    2013-10-01

    Trophy hunting can provide economic incentives to conserve wild species, but it can also involve risk when rare species are hunted. The anthropogenic Allee effect (AAE) is a conceptual model that seeks to explain how rarity may spread the seeds of further endangerment. The AAE model has increasingly been invoked in the context of trophy hunting, increasing concerns that such hunting may undermine rather than enhance conservation efforts. We question the appropriateness of uncritically applying the AAE model to trophy hunting for 4 reasons. First, the AAE assumes an open-access resource, which is a poor characterization of most trophy-hunting programs and obscures the potential for state, communal, or private-property use rights to generate positive incentives for conservation. Second, study results that show the price of hunting increases as the rarity of the animal increases are insufficient to indicate the presence of AAE. Third, AAE ignores the existence of biological and behavioral factors operating in most trophy-hunting contexts that tend to regulate the effect of hunting. We argue that site-specific data, rather than aggregated hunting statistics, are required to demonstrate that patterns of unsustainable exploitation can be well explained by an AAE model. Instead, we suggest that conservation managers seeking to investigate and identify constraints that limit the potential conservation role of trophy hunting, should focus on the critical governance characteristics that shape the potential conservation role of trophy hunting, such as corruption, insecure property rights, and inadequate sharing of benefits with local people. © 2013 Society for Conservation Biology.

  13. Global physical effects of anthropogenic hydrological alterations: sea level and water redistribution

    NASA Astrophysics Data System (ADS)

    Sahagian, Dork

    2000-07-01

    Human influence on the Earth System and hydrologic cycle has reached the point where it affects the hydrologic balance between ocean and continental storage reservoirs. The anthropogenic redistribution of water mass at a planetary scale even has an effect on Earth rotation parameters. Land use changes associated with expanding agriculture to support an increasing human population have already had a profound influence on basin-scale hydrology, and in extreme cases, on regional climate. Major human activities which lead to hydrologic alterations include irrigation (from ground water mining and surface water diversion), deforestation, wetland filling or drainage, and new dam construction. With the exception of the latter, these all contribute to the transfer of water from the continents to the ocean and a reduction of continental water resources. However, water impoundment behind dams may partially or completely counteract the cumulative effect of the others. Present compilations of reservoirs impounded by dams include only the results of major engineering projects. Smaller impoundments have largely been ignored. The cumulative volume of the literally millions of small reservoirs such as farm ponds and rice paddies may approach that of the larger documented reservoirs. Unfortunately it is not practical to make a global inventory of millions of small and unregistered reservoirs, so their volume may never be known precisely. The quantity of water stored in artifically raised water tables behind dams has also not yet been addressed. The issue of water impoundment or release from continental drainage basins affects global sea level. Recent estimates based solely on major dammed reservoirs suggest that if new dam construction is not maintained at the rates of the 1960s through 1980s, the rate of sea level rise could increase by about half a millimeter per year. If small impoundments are taken into account, this figure could be much greater.

  14. Water Balance Study on a Semiarid Regional Landscape in South Texas: Effects of Anthropogenic Land Disturbance

    NASA Astrophysics Data System (ADS)

    Camarena, C.; Ren, J.; Jones, K.

    2004-12-01

    While extensive vegetation manipulation has been encouraged by many administrators and extension groups, its effect on the water balance is complex and the hypothesis that removal of woody plants consistently reduces evapotranspiration, increases soil water content, and water yield remains unproven. This project focuses on examination of the effects of various land management practices on the overall water balance for semiarid regional landscapes. The project location is at the Wellhausen Ranch Research Station located near Laredo, TX, consisting of 5,280 acres of shrub landscape dominated by honey mesquite shrub species. This ranch has undergone various land disturbances such as root plowing and cattle overgrazing that have caused damage to the vegetation and natural communities. Five research sites were chosen within the ranch including a control site, a gravel dominated site, a root plowed site, an undisturbed site, and a second research site with different vegetative cover to represent different land use environments. Parameters that are being measured for the water balance study include precipitation, soil moisture, surface runoff, evaporation, and evapotranspiration. Preliminary results show that for the period of January to September of 2004, temperatures in the Wellhausen Ranch range from 29.1 ºF to 106.9 ºF, indicating hot summers and mild winters. 68 rainfall events have occurred, which resulted in 16.24 inches of total precipitation. Patterns were detected in soil moisture profiles reflecting the differences of soil moisture at different depths in the soil. Analysis of variance (ANOVA) indicates significant differences in the soil moisture in the five research sites. In addition, micro-lysimeter results show higher evaporation rates in the gravel dominated and the second research sites. These preliminary results indicate a potentially significant influence of anthropogenic land disturbance on a landscape water balance in the semiarid Nueces River basin.

  15. ICBEN review of research on the biological effects of noise 2011-2014

    PubMed Central

    Basner, Mathias; Brink, Mark; Bristow, Abigail; de Kluizenaar, Yvonne; Finegold, Lawrence; Hong, Jiyoung; Janssen, Sabine A; Klaeboe, Ronny; Leroux, Tony; Liebl, Andreas; Matsui, Toshihito; Schwela, Dieter; Sliwinska-Kowalska, Mariola; Sörqvist, Patrik

    2015-01-01

    The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health. PMID:25774609

  16. Cortical encoding of speech acoustics: Effects of noise and amplification.

    PubMed

    Kuruvilla-Mathew, Abin; Purdy, Suzanne C; Welch, David

    2015-01-01

    To investigate speech stimuli and background-noise-dependent changes in cortical auditory-evoked potentials (CAEPs) in unaided and aided conditions, and determine amplification effects on CAEPs. CAEPs to naturally produced syllables in quiet and in multi-talker babble were recorded, with and without a hearing aid in the right ear. At least 300 artifact-free trials for each participant were required to measure latencies and amplitudes of CAEPs. Acoustic characteristics of the hearing-aid-transduced stimuli were measured using in-the-canal probe microphone measurements to determine unaided versus aided SNR and to compare stimulus acoustic characteristics to CAEP findings. Ten participants with normal hearing, aged 19 to 35 years. CAEP latencies and amplitudes showed significant effects of speech contrast, background noise, and amplification. N1 and P2 components varied differently across conditions. In general, cortical processing in noise was influenced by SNR and the spectrum of the speech stimuli. Hearing-aid-induced spectral and temporal changes to the speech stimuli affected P1-N1-P2 components. Amplification produced complex effects on latencies and amplitudes across speech stimuli and CAEP components, and for quiet versus noise conditions. CAEP components reflect spectral and temporal characteristics of speech stimuli and acoustic changes induced by background noise and amplification.

  17. Noise sensitivity, rather than noise level, predicts the non-auditory effects of noise in community samples: a population-based survey.

    PubMed

    Park, Jangho; Chung, Seockhoon; Lee, Jiho; Sung, Joo Hyun; Cho, Seung Woo; Sim, Chang Sun

    2017-04-12

    Excessive noise affects human health and interferes with daily activities. Although environmental noise may not directly cause mental illness, it may accelerate and intensify the development of latent mental disorders. Noise sensitivity (NS) is considered a moderator of non-auditory noise effects. In the present study, we aimed to assess whether NS is associated with non-auditory effects. We recruited a community sample of 1836 residents residing in Ulsan and Seoul, South Korea. From July to November 2015, participants were interviewed regarding their demographic characteristics, socioeconomic status, medical history, and NS. The non-auditory effects of noise were assessed using the Center of Epidemiologic Studies Depression, Insomnia Severity index, State Trait Anxiety Inventory state subscale, and Stress Response Inventory-Modified Form. Individual noise levels were recorded from noise maps. A three-model multivariate logistic regression analysis was performed to identify factors that might affect psychiatric illnesses. Participants ranged in age from 19 to 91 years (mean: 47.0 ± 16.1 years), and 37.9% (n = 696) were male. Participants with high NS were more likely to have been diagnosed with diabetes and hyperlipidemia and to use psychiatric medication. The multivariable analysis indicated that even after adjusting for noise-related variables, sociodemographic factors, medical illness, and duration of residence, subjects in the high NS group were more than 2 times more likely to experience depression and insomnia and 1.9 times more likely to have anxiety, compared with those in the low NS group. Noise exposure level was not identified as an explanatory value. NS increases the susceptibility and hence moderates there actions of individuals to noise. NS, rather than noise itself, is associated with an elevated susceptibility to non-auditory effects.

  18. Environmental Effects on Affect: Density, Noise and Personality.

    ERIC Educational Resources Information Center

    Bharucha-Reid, Rodabe; Kivak, H. Asuman

    1982-01-01

    Research findings are reported of a study (N=88 undergraduate males) of molar crowding in urban centers which involved the simultaneous variation of social density, spatial density, noise, and personality as they effect room affect (physical and psychological). Several main effects proved significant. (Author/DC)

  19. Impacts of Different Anthropogenic Aerosol Emission Scenarios on Hydrology in the Mekong Basins and their Effects on Irrigation and Hydropower

    NASA Astrophysics Data System (ADS)

    Yeo, L. K.; Wang, C.

    2016-12-01

    Water distribution is closely linked to food and energy security. Aerosol emissions affect cloud properties, as well as atmospheric stability, changing the distribution of precipitation. These changes in precipitation causes changes in water availability, affecting food production and energy generation. These impacts are especially important in Southeast Asia, which uses up to 90% of their water supply for irrigation. In addition, the Mekong river, the largest inland fishery in the world, has 30,000MW of hydropower potential in its lower reaches alone. Modelling the impacts of these anthropogenic emission scenarios will allow us to better understand their downstream effects on hydrology, and any potential feedbacks it may have on future aerosol emissions. In the first step, we run the WRF model using FNL reanlaysis data from 2014 and 2015 to generate the WRF-hydro model forcing inputs. We then run the WRF-hydro model and compare the output with current measurements of soil moisture, river flow, and precipitation. Secondly, we run the WRF-Chem model with various anthropogenic emission scenarios and put the results through the WRF-hydro model to determine the impact of these emission scenarios on soil moisture and river flow. The scenarios include enhanced anthropogenic emissions in Asia, anologous to widespread adoption of coal burning as an energy source in Asia. Anthropogenic emissions have the potential to affect energy policy in countries affected by these emissions. When hydropower generation is affected by changes in precipitation, the affected countries will have to switch to alternative sources of fuel to meet their energy needs. These sources typically result in changes in anthropogenic aerosol emisssions, especially if coal is used as an alternative source of energy.

  20. Intermittent Noise Induces Physiological Stress in a Coastal Marine Fish

    PubMed Central

    Nichols, Tye A.; Anderson, Todd W.; Širović, Ana

    2015-01-01

    Anthropogenic noise in the ocean has increased substantially in recent decades, and motorized vessels produce what is likely the most common form of underwater noise pollution. Noise has the potential to induce physiological stress in marine fishes, which may have negative ecological consequences. In this study, physiological effects of increased noise (playback of boat noise recorded in the field) on a coastal marine fish (the giant kelpfish, Heterostichus rostratus) were investigated by measuring the stress responses (cortisol concentration) of fish to increased noise of various temporal dynamics and noise levels. Giant kelpfish exhibited acute stress responses when exposed to intermittent noise, but not to continuous noise or control conditions (playback of recorded natural ambient sound). These results suggest that variability in the acoustic environment may be more important than the period of noise exposure for inducing stress in a marine fish, and provide information regarding noise levels at which physiological responses occur. PMID:26402068

  1. Intermittent Noise Induces Physiological Stress in a Coastal Marine Fish.

    PubMed

    Nichols, Tye A; Anderson, Todd W; Širović, Ana

    2015-01-01

    Anthropogenic noise in the ocean has increased substantially in recent decades, and motorized vessels produce what is likely the most common form of underwater noise pollution. Noise has the potential to induce physiological stress in marine fishes, which may have negative ecological consequences. In this study, physiological effects of increased noise (playback of boat noise recorded in the field) on a coastal marine fish (the giant kelpfish, Heterostichus rostratus) were investigated by measuring the stress responses (cortisol concentration) of fish to increased noise of various temporal dynamics and noise levels. Giant kelpfish exhibited acute stress responses when exposed to intermittent noise, but not to continuous noise or control conditions (playback of recorded natural ambient sound). These results suggest that variability in the acoustic environment may be more important than the period of noise exposure for inducing stress in a marine fish, and provide information regarding noise levels at which physiological responses occur.

  2. Colored noise and memory effects on formal spiking neuron models.

    PubMed

    da Silva, L A; Vilela, R D

    2015-06-01

    Simplified neuronal models capture the essence of the electrical activity of a generic neuron, besides being more interesting from the computational point of view when compared to higher-dimensional models such as the Hodgkin-Huxley one. In this work, we propose a generalized resonate-and-fire model described by a generalized Langevin equation that takes into account memory effects and colored noise. We perform a comprehensive numerical analysis to study the dynamics and the point process statistics of the proposed model, highlighting interesting new features such as (i) nonmonotonic behavior (emergence of peak structures, enhanced by the choice of colored noise characteristic time scale) of the coefficient of variation (CV) as a function of memory characteristic time scale, (ii) colored noise-induced shift in the CV, and (iii) emergence and suppression of multimodality in the interspike interval (ISI) distribution due to memory-induced subthreshold oscillations. Moreover, in the noise-induced spike regime, we study how memory and colored noise affect the coherence resonance (CR) phenomenon. We found that for sufficiently long memory, not only is CR suppressed but also the minimum of the CV-versus-noise intensity curve that characterizes the presence of CR may be replaced by a maximum. The aforementioned features allow to interpret the interplay between memory and colored noise as an effective control mechanism to neuronal variability. Since both variability and nontrivial temporal patterns in the ISI distribution are ubiquitous in biological cells, we hope the present model can be useful in modeling real aspects of neurons.

  3. Colored noise and memory effects on formal spiking neuron models

    NASA Astrophysics Data System (ADS)

    da Silva, L. A.; Vilela, R. D.

    2015-06-01

    Simplified neuronal models capture the essence of the electrical activity of a generic neuron, besides being more interesting from the computational point of view when compared to higher-dimensional models such as the Hodgkin-Huxley one. In this work, we propose a generalized resonate-and-fire model described by a generalized Langevin equation that takes into account memory effects and colored noise. We perform a comprehensive numerical analysis to study the dynamics and the point process statistics of the proposed model, highlighting interesting new features such as (i) nonmonotonic behavior (emergence of peak structures, enhanced by the choice of colored noise characteristic time scale) of the coefficient of variation (CV) as a function of memory characteristic time scale, (ii) colored noise-induced shift in the CV, and (iii) emergence and suppression of multimodality in the interspike interval (ISI) distribution due to memory-induced subthreshold oscillations. Moreover, in the noise-induced spike regime, we study how memory and colored noise affect the coherence resonance (CR) phenomenon. We found that for sufficiently long memory, not only is CR suppressed but also the minimum of the CV-versus-noise intensity curve that characterizes the presence of CR may be replaced by a maximum. The aforementioned features allow to interpret the interplay between memory and colored noise as an effective control mechanism to neuronal variability. Since both variability and nontrivial temporal patterns in the ISI distribution are ubiquitous in biological cells, we hope the present model can be useful in modeling real aspects of neurons.

  4. Effects of motion on jet exhaust noise from aircraft

    NASA Technical Reports Server (NTRS)

    Chun, K. S.; Berman, C. H.; Cowan, S. J.

    1976-01-01

    The various problems involved in the evaluation of the jet noise field prevailing between an observer on the ground and an aircraft in flight in a typical takeoff or landing approach pattern were studied. Areas examined include: (1) literature survey and preliminary investigation, (2) propagation effects, (3) source alteration effects, and (4) investigation of verification techniques. Sixteen problem areas were identified and studied. Six follow-up programs were recommended for further work. The results and the proposed follow-on programs provide a practical general technique for predicting flyover jet noise for conventional jet nozzles.

  5. The effect of interior aircraft noise on pilot performance.

    PubMed

    Lindvall, Johan; Västfjall, Daniel

    2013-04-01

    This study examined the effect of the interior sounds of an aircraft cockpit on ratings of affect and expected performance decrement. While exposed to 12 interior aircraft sounds, of which half were modified to correspond to what is experienced with an active noise reduction (ANR) headset, 23 participants rated their affective reactions and how they believed their performance on various tasks would be affected. The results suggest that implementation of ANR-technique has a positive effect on ratings of expected performance. In addition, affective reactions to the noise are related to ratings of expected performance. The implications of these findings for both research and pilot performance are discussed.

  6. Effects of cell cycle noise on excitable gene circuits

    NASA Astrophysics Data System (ADS)

    Veliz-Cuba, Alan; Gupta, Chinmaya; Bennett, Matthew R.; Josić, Krešimir; Ott, William

    2016-12-01

    We assess the impact of cell cycle noise on gene circuit dynamics. For bistable genetic switches and excitable circuits, we find that transitions between metastable states most likely occur just after cell division and that this concentration effect intensifies in the presence of transcriptional delay. We explain this concentration effect with a three-states stochastic model. For genetic oscillators, we quantify the temporal correlations between daughter cells induced by cell division. Temporal correlations must be captured properly in order to accurately quantify noise sources within gene networks.

  7. Effects of Anthropogenic Nitrogen Loading on Riverine Nitrogen Export in the Northeastern USA

    NASA Astrophysics Data System (ADS)

    Boyer, E. W.; Goodale, C. L.; Howarth, R. W.

    2001-05-01

    Human activities have greatly altered the nitrogen (N) cycle, accelerating the rate of N fixation in landscapes and delivery of N to water bodies. To examine the effects of anthropogenic N inputs on riverine N export, we quantified N inputs and riverine N loss for 16 catchments along a latitudinal profile from Maine to Virginia, which encompass a range of climatic variability and are major drainages to the coast of the North Atlantic Ocean. We quantified inputs of N to each catchment: atmospheric deposition, fertilizer application, agricultural and forest biological N fixation, and the net import of N in food and feed. We compared these inputs with N losses from the system in riverine export. The importance of the relative sources varies widely by watershed and is related to land use. Atmospheric deposition was the largest source (>60%) to the forested catchments of northern New England (e.g., Penobscot and Kennebec); import of N in food was the largest source of N to the more populated regions of southern New England (e.g., Charles and Blackstone); and agricultural inputs were the dominant N sources in the Mid-Atlantic region (e.g., Schuylkill and Potomac). Total N inputs to each catchment increased with percent cover in agriculture and urban land, and decreased with percent forest. Over the combined area of the catchments, net atmospheric deposition was the largest single source input (34%), followed by imports of N in food and feed (24%), fixation in agricultural lands (21%), fertilizer use (15%), and fixation in forests (6%). Riverine export of N is well correlated with N inputs, but it accounts for only a fraction (28%) of the total N inputs. This work provides an understanding of the sources of N in landscapes, and highlights how human activities impact N cycling in the northeast region.

  8. Evaluation of anthropogenic effects on water quality and bacterial diversity in Rawal Lake, Islamabad.

    PubMed

    Saeed, Asma; Hashmi, Imran

    2014-05-01

    Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant.

  9. Effects of wetland vs. landscape variables on parasite communities of Rana pipiens: links to anthropogenic factors

    USGS Publications Warehouse

    Schotthoefer, Anna M.; Rohr, Jason R.; Cole, Rebecca A.; Koehler, Anson V.; Johnson, Catherine M.; Johnson, Lucinda B.; Beasley, Val R.

    2011-01-01

    The emergence of several diseases affecting amphibian populations worldwide has prompted investigations into determinants of the occurrence and abundance of parasites in frogs. To understand the spatial scales and identify specific environmental factors that determine risks of parasitism in frogs, helminth communities in metamorphic frogs of the northern leopard frog (Rana pipiens) were examined in relation to wetland and landscape factors at local (1 km) and regional (10 km) spatial extents in an agricultural region of Minnesota (USA) using regression analyses, ordination, and variance partitioning techniques. Greater amounts of forested and woody wetland habitats, shorter distances between woody wetlands, and smaller-sized open water patches in surrounding landscapes were the most consistently positive correlates with the abundances, richness, and diversity of helminths found in the frogs. Wetland and local landscape variables were suggested as most important for larval trematode abundances, whereas local and regional landscape variables appeared most important for adult helminths. As previously reported, the sum concentration of atrazine and its metabolite desethylatrazine, was the strongest predictor of larval trematode communities. In this report, we highlight the additional influences of landscape factors. In particular, our data suggest that anthropogenic activities that have resulted in the loss of the availability and connectivity of suitable habitats in the surrounding landscapes of wetlands are associated with declines in helminth richness and abundance, but that alteration of wetland water quality through eutrophication or pesticide contamination may facilitate the transmission of certain parasite taxa when they are present at wetlands. Although additional research is needed to quantify the negative effects of parasitism on frog populations, efforts to reduce inputs of agrochemicals into wetlands to limit larval trematode infections may be warranted

  10. Tectonic and Anthropogenic Effects on Increased Intraplate Seismicity: The Oklahoma Case

    NASA Astrophysics Data System (ADS)

    Germanovich, L. N.; Reches, Z.; Carpenter, B. M.; Ghassemi, A.; Wdowinski, S.; Baer, G.

    2016-12-01

    The drastic surge of earthquake activity in Oklahoma since 2010 is widely viewed as the result of wastewater injection, which is a by-product of oil/gas production. It is well known that injection can raise the pore-pressure within a fault-zone and induce earthquakes, however, the general processes that govern the interactions between intraplate tectonic settings, anthropogenic activity and increase in seismicity are still not well understood. For example, why do most earthquakes in Oklahoma occur in the basement while almost all injection takes place in the sedimentary cover? What are the effects of injected water on the strength of basement rocks? Do the earthquakes indicate crustal-scale deformation? What are the relationships between the regional in-situ stresses and the local structures? We are addressing these questions by an approach that includes geodesy, structural analysis, crustal modeling and rock-mechanics experiments. The relationships between injection, tectonics and seismicity in Oklahoma are viewed through three geodynamic modes: (A) prolonged, large-scale injection that leads to weakening and deformation of the basement; (B) intense, local injection that may activate large faults through direct flow pathways; and (C) large-scale removal/injection of fluids in the sedimentary sequence that redistributes mass and pressure. The preliminary results indicate that these modes can be distinguished by the following analyses: (a) characterization of the 2005-2017 crustal deformation of Oklahoma by InSAR and GPS analyses; (b) analytical and numerical simulations of crustal deformation in light of the above three modes; (c) in-situ stress analysis based on focal-plane solutions; and (d) characterization of basement fault architecture at exposed basement regions and analysis of the mechanical properties of Oklahoma basement rocks.

  11. Mitigating the effects of measurement noise on Granger causality

    SciTech Connect

    Nalatore, Hariharan; Ding Mingzhou; Rangarajan, Govindan

    2007-03-15

    Computing Granger causal relations among bivariate experimentally observed time series has received increasing attention over the past few years. Such causal relations, if correctly estimated, can yield significant insights into the dynamical organization of the system being investigated. Since experimental measurements are inevitably contaminated by noise, it is thus important to understand the effects of such noise on Granger causality estimation. The first goal of this paper is to provide an analytical and numerical analysis of this problem. Specifically, we show that, due to noise contamination (1) spurious causality between two measured variables can arise and (2) true causality can be suppressed. The second goal of the paper is to provide a denoising strategy to mitigate this problem. Specifically, we propose a denoising algorithm based on the combined use of the Kalman filter theory and the expectation-maximization algorithm. Numerical examples are used to demonstrate the effectiveness of the denoising approach.

  12. Effects of bidirectional regulation on noises in gene networks.

    PubMed

    Zheng, Xiudeng; Tao, Yi

    2010-03-14

    To investigate the effects of bidirectional regulation on the noise in protein concentration, a theoretical and simple three-gene network model is considered. The basic idea behind this model is from Paulsson's proposition (J. Paulsson, Phys. Life Rev. 2005, 2, 157-175), where the synthesis and degradation of a mRNA species corresponding to a target protein are regulated directly and indirectly by a certain sigma-factor, and a random increase in the concentration of the sigma-factor should increase both the synthesis and degradation rates of the mRNA species (bidirectional regulation). Using the standard Omega-expansion technique (linear noise approximation) and Monte Carlo simulation, our main results show clearly that for the steady-state statistics the effects of the noise of the sigma-factor on the stochastic fluctuation of the target protein could partially cancel out.

  13. Anthropogenic effects on soil quality in ancient terraced agricultural fields of Chihuahua, Mexico

    USDA-ARS?s Scientific Manuscript database

    Agricultural soil quality was investigated in ancient field systems near Casas Grandes (also known as Paquimé), one of the largest and most complex prehistoric settlements in the North American Southwest. This research was completed as part of an interdisciplinary study of the anthropogenic ecology...

  14. Fate and Effects of Anthropogenic Chemicals in Mangrove Ecosystems: A Review

    EPA Science Inventory

    The role of anthropogenic chemicals in the decline of plant-dominated, fringe ecosystems such as mangroves is important to understand. Mangrove global coverage has been reduced approximately 50% in recent years and the presence of toxic chemicals may be a contributing factor. T...

  15. Fate and Effects of Anthropogenic Chemicals in Mangrove Ecosystems: A Review

    EPA Science Inventory

    The role of anthropogenic chemicals in the decline of plant-dominated, fringe ecosystems such as mangroves is important to understand. Mangrove global coverage has been reduced approximately 50% in recent years and the presence of toxic chemicals may be a contributing factor. T...

  16. Interactive effects of anthropogenic nitrogen enrichment and climate change on terrestrial and aquatic biodiversity

    EPA Science Inventory

    Climate change and Nr from anthropogenic activities are causing some of the most rapid changes in biodiversity in recent times. Climate change is causing warming trends that result in poleward and elevational range shiftsof flora and fauna, and changes in phenology, particularly ...

  17. Interactive effects of anthropogenic nitrogen enrichment and climate change on terrestrial and aquatic biodiversity

    EPA Science Inventory

    Climate change and Nr from anthropogenic activities are causing some of the most rapid changes in biodiversity in recent times. Climate change is causing warming trends that result in poleward and elevational range shiftsof flora and fauna, and changes in phenology, particularly ...

  18. The effect of opponent noise on image quality

    NASA Astrophysics Data System (ADS)

    Johnson, Garrett M.; Fairchild, Mark D.

    2005-01-01

    A psychophysical experiment was performed examining the effect of luminance and chromatic noise on perceived image quality. The noise was generated in a recently developed isoluminant opponent space. 5 spatial frequency octave bands centered at 2, 4, 8, 16, and 32 cycles-per-degree (cpd) of visual angle were generated for each of the luminance, red-green, and blue-yellow channels. Two levels of contrast at each band were examined. Overall there were 30 images and 1 "original" image. Four different image scenes were used in a paired-comparison experiment. Observers were asked to select the image that appears to be of higher quality. The paired comparison data were used to generate interval scales of image quality using Thurstone's Law of Comparative Judgments. These interval scales provide insight into the effect of noise on perceived image quality. Averaged across the scenes, the original noise-free image was determined to be of highest quality. While this result is not surprising on its own, examining several of the individual scenes shows that adding low-contrast blue-yellow isoluminant noise does not statistically decrease image quality and can result in a slight increase in quality.

  19. The effect of opponent noise on image quality

    NASA Astrophysics Data System (ADS)

    Johnson, Garrett M.; Fairchild, Mark D.

    2004-10-01

    A psychophysical experiment was performed examining the effect of luminance and chromatic noise on perceived image quality. The noise was generated in a recently developed isoluminant opponent space. 5 spatial frequency octave bands centered at 2, 4, 8, 16, and 32 cycles-per-degree (cpd) of visual angle were generated for each of the luminance, red-green, and blue-yellow channels. Two levels of contrast at each band were examined. Overall there were 30 images and 1 "original" image. Four different image scenes were used in a paired-comparison experiment. Observers were asked to select the image that appears to be of higher quality. The paired comparison data were used to generate interval scales of image quality using Thurstone's Law of Comparative Judgments. These interval scales provide insight into the effect of noise on perceived image quality. Averaged across the scenes, the original noise-free image was determined to be of highest quality. While this result is not surprising on its own, examining several of the individual scenes shows that adding low-contrast blue-yellow isoluminant noise does not statistically decrease image quality and can result in a slight increase in quality.

  20. The Effects of Numerical Noise on Perturbation Experiments

    NASA Astrophysics Data System (ADS)

    Ancell, B. C.

    2016-12-01

    Perturbation experiments are used widely within numerical weather prediction models to investigate the effects of initial condition error and data assimilation on atmospheric forecasts. It has been discovered that perturbations within the Weather Research and Forecasting (WRF) model create numerical noise that propagates horizontally at speeds substantially faster than any realistic physical mode. This noise is very small, and likely does not affect the atmospheric state within model simulations in areas where dry dynamics dominate. However, in areas of moist convection or precipitation, the noise can grow rapidly through chaotic processes to significantly alter the state, potentially growing upscale. The growth of noise thus has the ability to cause a misinterpretation of the realistic effects of the perturbation in the first place. This work details the propagation and growth of numerical noise in the WRF model for a simulation of convection, and compares it to a number of perturbation experiments for which realistic perturbation growth is expected. The implications of these results in the greater body of literature is discussed.

  1. Noise pollution is pervasive in U.S. protected areas.

    PubMed

    Buxton, Rachel T; McKenna, Megan F; Mennitt, Daniel; Fristrup, Kurt; Crooks, Kevin; Angeloni, Lisa; Wittemyer, George

    2017-05-05

    Anthropogenic noise threatens ecological systems, including the cultural and biodiversity resources in protected areas. Using continental-scale sound models, we found that anthropogenic noise doubled background sound levels in 63% of U.S. protected area units and caused a 10-fold or greater increase in 21%, surpassing levels known to interfere with human visitor experience and disrupt wildlife behavior, fitness, and community composition. Elevated noise was also found in critical habitats of endangered species, with 14% experiencing a 10-fold increase in sound levels. However, protected areas with more stringent regulations had less anthropogenic noise. Our analysis indicates that noise pollution in protected areas is closely linked with transportation, development, and extractive land use, providing insight into where mitigation efforts can be most effective. Copyright © 2017, American Association for the Advancement of Science.

  2. Effects of anthropogenic aerosols on temperature changes in China during the twentieth century based on CMIP5 models

    NASA Astrophysics Data System (ADS)

    Li, Chunxiang; Zhao, Tianbao; Ying, Kairan

    2016-08-01

    Using three models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), we compare the direct and other effects of anthropogenic aerosols on observed and simulated annual, winter, and summer temperature changes. Three regions, namely, arid-semiarid area, humid-semiarid area, and the whole of China, are studied. The temperature changes caused by other effects of anthropogenic aerosol (OE) are calculated from the difference between the anthropogenic aerosol forcing run (AA) and the anthropogenic aerosol direct effect forcing run (DE). When the combined effects are considered, a significant area-averaged cooling rate varies in the range of -0.86 to -0.76 °C per century throughout China. Meanwhile, the isolated direct and other effects lower the temperature nationwide by -0.66 to -0.55 °C per century, and -0.31 to -0.11 °C per century, respectively. From a nonlinear perspective, the aerosol-induced temperature experiences a cooling trend, with AA having the largest cooling trend changes both annually and in the summer, while DE has the greatest reduction in the winter. Additionally, the influence of OE cannot be detected in observed annual changes over the arid-semiarid area and the whole of China, while the others are clearly detectable in all cases. AA (DE, OE) reduces the observational temperature mainly over the humid-semihumid region, where the contribution to the observed warming ranges from -515.2 % (-298.7 %, -198.9 %) to -173.6 % (-130.3 %, -66.4 %).

  3. Aquatic noise pollution: implications for individuals, populations, and ecosystems.

    PubMed

    Kunc, Hansjoerg P; McLaughlin, Kirsty Elizabeth; Schmidt, Rouven

    2016-08-17

    Anthropogenically driven environmental changes affect our planet at an unprecedented scale and are considered to be a key threat to biodiversity. According to the World Health Organization, anthropogenic noise is one of the most hazardous forms of anthropogenically driven environmental change and is recognized as a major global pollutant. However, crucial advances in the rapidly emerging research on noise pollution focus exclusively on single aspects of noise pollution, e.g. on behaviour, physiology, terrestrial ecosystems, or on certain taxa. Given that more than two-thirds of our planet is covered with water, there is a pressing need to get a holistic understanding of the effects of anthropogenic noise in aquatic ecosystems. We found experimental evidence for negative effects of anthropogenic noise on an individual's development, physiology, and/or behaviour in both invertebrates and vertebrates. We also found that species differ in their response to noise, and highlight the potential underlying mechanisms for these differences. Finally, we point out challenges in the study of aquatic noise pollution and provide directions for future research, which will enhance our understanding of this globally present pollutant.

  4. Aquatic noise pollution: implications for individuals, populations, and ecosystems

    PubMed Central

    Kunc, Hansjoerg P.; McLaughlin, Kirsty Elizabeth; Schmidt, Rouven

    2016-01-01

    Anthropogenically driven environmental changes affect our planet at an unprecedented scale and are considered to be a key threat to biodiversity. According to the World Health Organization, anthropogenic noise is one of the most hazardous forms of anthropogenically driven environmental change and is recognized as a major global pollutant. However, crucial advances in the rapidly emerging research on noise pollution focus exclusively on single aspects of noise pollution, e.g. on behaviour, physiology, terrestrial ecosystems, or on certain taxa. Given that more than two-thirds of our planet is covered with water, there is a pressing need to get a holistic understanding of the effects of anthropogenic noise in aquatic ecosystems. We found experimental evidence for negative effects of anthropogenic noise on an individual's development, physiology, and/or behaviour in both invertebrates and vertebrates. We also found that species differ in their response to noise, and highlight the potential underlying mechanisms for these differences. Finally, we point out challenges in the study of aquatic noise pollution and provide directions for future research, which will enhance our understanding of this globally present pollutant. PMID:27534952

  5. Traffic noise reduces foraging efficiency in wild owls

    PubMed Central

    Senzaki, Masayuki; Yamaura, Yuichi; Francis, Clinton D.; Nakamura, Futoshi

    2016-01-01

    Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls’ ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls’ ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise. PMID:27537709

  6. Traffic noise reduces foraging efficiency in wild owls

    NASA Astrophysics Data System (ADS)

    Senzaki, Masayuki; Yamaura, Yuichi; Francis, Clinton D.; Nakamura, Futoshi

    2016-08-01

    Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls’ ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls’ ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise.

  7. Effect of Remote Sensory Noise on Hand Function Post Stroke

    PubMed Central

    Seo, Na Jin; Kosmopoulos, Marcella Lyn; Enders, Leah R.; Hur, Pilwon

    2014-01-01

    Hand motor impairment persists after stroke. Sensory inputs may facilitate recovery of motor function. This pilot study tested the effectiveness of tactile sensory noise in improving hand motor function in chronic stroke survivors with tactile sensory deficits, using a repeated measures design. Sensory noise in the form of subthreshold, white noise, mechanical vibration was applied to the wrist skin during motor tasks. Hand dexterity assessed by the Nine Hole Peg Test and the Box and Block Test and pinch strength significantly improved when the sensory noise was turned on compared with when it was turned off in chronic stroke survivors. The subthreshold sensory noise to the wrist appears to induce improvements in hand motor function possibly via neuronal connections in the sensoriomotor cortex. The approach of applying concomitant, unperceivable mechanical vibration to the wrist during hand motor tasks is easily adoptable for clinic use as well as unsupervised home use. This pilot study suggests a potential for a wristband-type assistive device to complement hand rehabilitation for stroke survivors with sensorimotor deficit. PMID:25477806

  8. Recruitment-of-loudness effects of attenuative noise reduction algorithms

    NASA Astrophysics Data System (ADS)

    Whitmal, Nathaniel; Vosoughi, Azadeh

    2002-05-01

    Hearing-impaired listeners have greater difficulty understanding speech in noise than normal-hearing listeners do. As a result, hearing aid users are often challenged by the inability of their hearing aids to improve intelligibility in noise. Several investigators have addressed this problem by using well-known signal processing methods (e.g., spectral subtraction, Wiener filtering) to enhance noise-corrupted speech. Unfortunately, these methods have failed to provide significant improvements in intelligibility. One possible explanation is the level-dependent nature of the attenuation that the algorithms impose on the speech. In the cases described above, this attenuation resembles the piecewise-linear input-output characteristic observed in certain recruitment-of-loudness simulators. The purpose of this study was to compare the intelligibility of processed speech with that expected for recruitment-of-loudness simulation. Trials of the CUNY Nonsense Syllable Test were conducted with 12 normal-hearing listeners, using syllables that were mixed with additive noise at SNRs of 6, 12, and 18 dB. Input-output characteristics for the signals were measured and used to determine the effective threshold shift imposed by the algorithms. Comparisons of measured intelligibility scores with articulation index-based intelligibility predictions indicate that the behavior of such noise reduction algorithms can be successfully modeled as a form of mild sensorineural hearing loss.

  9. Incidence angle effects on convected gust airfoil noise

    NASA Technical Reports Server (NTRS)

    Kerschen, E. J.; Myers, M. R.

    1983-01-01

    An analysis is developed which predicts the influence of airfoil mean loading on noise generation due to convected gusts. The theory is based on a linearization of the exact inviscid equations about a nonuniform compressible mean flow and the solution is developed using singular perturbation techniques. The case of a flat plate airfoil, at incidence angle alpha, interacting with three-dimensional disturbances is analyzed. It is found that in the vicinity of the airfoil leading and trailing edges, local regions are present which scale on the disturbance wavelength, with the noise generation concentrated in these regions. Away from the airfoil edges, the mean flow variation is found to be slow compared to the disturbance wavelength and no significant noise generation occurs. The mean flow variation near the leading edge generates additional noise by distorting the convected gust. The cumulative effect of the airfoil mean loading in the trailing edge region produces a 0(1) phase shift between the disturbances on the upper and lower surfaces of the airfoil. A corresponding 0(1) decrease, compared to the alpha = 0 case, is found in the noise generated at the trailing edge.

  10. The effects of noise on speech and warning signals

    NASA Astrophysics Data System (ADS)

    Suter, Alice H.

    1989-06-01

    To assess the effects of noise on speech communication it is necessary to examine certain characteristics of the speech signal. Speech level can be measured by a variety of methods, none of which has yet been standardized, and it should be kept in mind that vocal effort increases with background noise level and with different types of activity. Noise and filtering commonly degrade the speech signal, especially as it is transmitted through communications systems. Intelligibility is also adversely affected by distance, reverberation, and monaural listening. Communication systems currently in use may cause strain and delays on the part of the listener, but there are many possibilities for improvement. Individuals who need to communicate in noise may be subject to voice disorders. Shouted speech becomes progressively less intelligible at high voice levels, but improvements can be realized when talkers use clear speech. Tolerable listening levels are lower for negative than for positive S/Ns, and comfortable listening levels should be at a S/N of at least 5 dB, and preferably above 10 dB. Popular methods to predict speech intelligibility in noise include the Articulation Index, Speech Interference Level, Speech Transmission Index, and the sound level meter's A-weighting network. This report describes these methods, discussing certain advantages and disadvantages of each, and shows their interrelations.

  11. Wind noise in hearing aids: II. Effect of microphone directivity.

    PubMed

    Chung, King

    2012-01-01

    The objectives were: (1) to examine the effects of a directional microphone with different directivity patterns and different microphone combinations on wind noise levels at the hearing aid output; and (2) to derive strategies appropriate for hearing aid selection and future designs. The in-situ frequency responses of a behind-the-ear hearing aid (BTE1) were matched when the hearing aid was programmed to dipole, hypercardioid, cardioids, or adaptive microphone mode. The in-situ frequency responses of another hearing aid (BTE2) were matched among an omnidirectional microphone (OMNI), an adaptive directional microphone (ADM), and a combination of an omnidirectional microphone at low frequencies and an adaptive directional microphone at high frequencies (MIXED). Flow noise was recorded at flow velocities of 0, 4.5, 9.0, and 13.5 m/s. Measurements were repeated for the hypercardioid pattern of BTE1. Flow noise recorded using directional microphones with four directivity patterns and using OMNI, ADM, and MIXED. Directional microphones with different directivity patterns generated similar flow noise levels. ADM yielded higher overall levels than OMNI and MIXED, which had similar overall levels. The adaptive directional microphone is the most versatile microphone for use in wind. The mixed microphone mode is a viable wind noise reduction option.

  12. Auditory effects of noise on infant and adult guinea pigs.

    PubMed

    Danto, J; Caiazzo, A J

    1977-01-01

    This pilot study compared the susceptibility of the infant (48 hr) and adult (120 days) guinea pig to the effects of noise. Subjects were exposed to a narrow band of noise (center frequency 4 kHz) at an intensity of 115 dB sound pressure level (SPL) for 1 hr. Postexposure thresholds were obtained by a conditioned suppression technique. Results indicated that the infant animals displayed a mean hearing threshold of 25 dB SPL that significantly differed from the adult mean threshold of 7.5 dB SPL.

  13. Enhanced shot noise in carbon nanotube field-effect transistors

    SciTech Connect

    Betti, A.; Fiori, G.; Iannaccone, G.

    2009-12-21

    We predict shot noise enhancement in defect-free carbon nanotube field-effect transistors through a numerical investigation based on the self-consistent solution of the Poisson and Schroedinger equations within the nonequilibrium Green's functions formalism, and on a Monte Carlo approach to reproduce injection statistics. Noise enhancement is due to the correlation between trapping of holes from the drain into quasibound states in the channel and thermionic injection of electrons from the source, and can lead to an appreciable Fano factor of 1.22 at room temperature.

  14. Cryogenically Cooled Field Effect Transistors for Low-Noise Systems

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  15. Cryogenetically Cooled Field Effect Transistors for Low-Noise Systems

    NASA Technical Reports Server (NTRS)

    Wollack, Edward J.; Rabin, Douglas M. (Technical Monitor)

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  16. Noise effect on fidelity of two-qubit teleportation

    SciTech Connect

    Hu Xueyuan; Gu Ying; Gong Qihuang; Guo Guangcan

    2010-05-15

    We investigate the effect of noise on a class of four-qubit entangled channels for two-qubit teleportation from Alice to Bob. These entangled channels include both parallel Bell pairs and inseparable channels with genuine multipartite entanglement. For the situation where only Bob's share of the entangled channel is subject to decoherence, we show by deriving a general expression for the teleported state that teleportation using noisy inseparable channels is equivalent to teleportation using noisy Bell pairs. When Alice's qubits are also subject to noise, we find that the inseparable channels never give a higher teleportation fidelity than Bell pairs, even in the presence of collective noise. Our results can shed some light on practical two-qubit teleportation.

  17. Effects of Classroom Acoustics and Self-Reported Noise Exposure on Teachers' Well-Being

    ERIC Educational Resources Information Center

    Kristiansen, Jesper; Persson, Roger; Lund, Soren Peter; Shibuya, Hitomi; Nielsen, Per Moberg

    2013-01-01

    Beyond noise annoyance and voice problems, little is known about the effects that noise and poor classroom acoustics have on teachers' health and well-being. The aim of this field study was therefore to investigate the effects of perceived noise exposure and classroom reverberation on measures of well-being. Data on self-reported noise exposure,…

  18. Effects of Classroom Acoustics and Self-Reported Noise Exposure on Teachers' Well-Being

    ERIC Educational Resources Information Center

    Kristiansen, Jesper; Persson, Roger; Lund, Soren Peter; Shibuya, Hitomi; Nielsen, Per Moberg

    2013-01-01

    Beyond noise annoyance and voice problems, little is known about the effects that noise and poor classroom acoustics have on teachers' health and well-being. The aim of this field study was therefore to investigate the effects of perceived noise exposure and classroom reverberation on measures of well-being. Data on self-reported noise exposure,…

  19. Aircraft noise and incidence of hypertension--gender specific effects.

    PubMed

    Eriksson, Charlotta; Bluhm, Gösta; Hilding, Agneta; Ostenson, Claes-Göran; Pershagen, Göran

    2010-11-01

    Recent studies show associations between aircraft noise and cardiovascular outcomes such as hypertension. However, these studies were mostly cross-sectional and there are uncertainties regarding potential gender differences as well as sensitive subgroups. In this study, we investigated the cumulative incidence of hypertension in relation to aircraft noise exposure among Swedish men and women living in Stockholm County. A total of 4721 subjects, aged 35-56 at baseline, were followed for 8-10 years. The population was selected according to family history of diabetes, which was present for half of the subjects. The exposure assessment was performed by geographical information systems and based on residential history during the period of follow-up. Blood pressure was measured at baseline and at the end of follow-up. Additional information regarding diagnosis and treatment of hypertension as well as various lifestyle factors was provided by questionnaires. In the overall population, no increased risk for hypertension was found among subjects exposed to aircraft noise ≥ 50 dB(A) L(den); relative risk (RR) 1.02 (95% CI 0.90-1.15). When restricting the cohort to those not using tobacco at the blood pressure measurements, a significant risk increase per 5 dB(A) of aircraft noise exposure was found in men; RR 1.21 (1.05-1.39), but not in women; RR 0.97 (0.83-1.13). In both sexes combined, an increased risk of hypertension related to aircraft noise exposure was indicated primarily among those reporting annoyance to aircraft noise; RR 1.42 (1.11-1.82). No consistent effect modification was detected for any of the cardiovascular risk factors under investigation although a family history of diabetes appeared to modify the risk in women. In conclusion, the results suggest an increased risk of hypertension following long-term aircraft noise exposure in men, and that subjects annoyed by aircraft noise may be particularly sensitive to noise related hypertension. Copyright © 2010

  20. Long-range atmospheric transport and deposition of anthropogenic contaminants and their potential effects on terrestrial ecosystems. Book chapter

    SciTech Connect

    Moser, T.J.; Barker, J.R.; Tingey, D.T.

    1991-01-01

    Through the processes of atmospheric transport and deposition, many anthropogenic contaminants such as industrial organics, pesticides, and trace metals have become widely distributed around the globe. Due to the phenomenon of long-range atmospheric transport, even the most remote areas of the plant are not out of range of contaminants emitted from distant anthropogenic sources. Many of these airborne contaminants are toxic and persistent, can bioaccumulate, and may remain biologically harmful for long periods of time. Although airborne contaminants are considered primarily a human health problem, there is increasing concern that they may have deleterious ecological consequences. When sensitive terrestrial plants and other biota experience chronic exposure to low concentrations of airborne toxic chemicals, sublethal effects may occur, with subsequent impacts on ecosystem structure and function.

  1. Multiplicative noise effects on electroconvection in controlling additive noise by a magnetic field.

    PubMed

    Huh, Jong-Hoon

    2015-12-01

    We report multiplicative noise-induced threshold shift of electroconvection (EC) in the presence of a magnetic field H. Controlling the thermal fluctuation (i.e., additive noise) of the rodlike molecules of nematic liquid crystals by H, the EC threshold is examined at various noise levels [characterized by their intensity and cutoff frequency (f(c))]. For a sufficiently strong H (i.e., ignorable additive noise), a modified noise sensitivity characterizing the shift problem is in good agreement with experimental results for colored as well as white noise (f(c)→∞); until now, there was a large deviation for (sufficiently) colored noises. The present study shows that H provides us with ideal conditions for studying the corresponding Carr-Helfrich theory considering pure multiplicative noise.

  2. Satellite Observations of the Effect of Natural and Anthropogenic Aerosols on Clouds

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.

    2006-01-01

    Our knowledge of atmospheric aerosols (smoke, pollution, dust or sea salt particles, small enough to be suspended in the air), their evolution, composition, variability in space and time and interaction with clouds and precipitation is still lacking despite decades of research. Understanding the global aerosol system is critical to quantifying anthropogenic climate change, to determine climate sensitivity from observations and to understand the hydrological cycle. While a single instrument was used to demonstrate 50 years ago that the global CO2 levels are rising, posing threat of global warming, we need an array of satellites and field measurements coupled with chemical transport models to understand the global aerosol system. This complexity of the aerosol problem results from their short lifetime (1 week) and variable chemical composition. A new generation of satellites provides exciting opportunities to measure the global distribution of aerosols, distinguishing natural from anthropogenic aerosol and measuring their interaction with clouds and climate.

  3. Satellite Observations of the Effect of Natural and Anthropogenic Aerosols on Clouds

    NASA Technical Reports Server (NTRS)

    Kaufman, Yoram J.

    2006-01-01

    Our knowledge of atmospheric aerosols (smoke, pollution, dust or sea salt particles, small enough to be suspended in the air), their evolution, composition, variability in space and time and interaction with clouds and precipitation is still lacking despite decades of research. Understanding the global aerosol system is critical to quantifying anthropogenic climate change, to determine climate sensitivity from observations and to understand the hydrological cycle. While a single instrument was used to demonstrate 50 years ago that the global CO2 levels are rising, posing threat of global warming, we need an array of satellites and field measurements coupled with chemical transport models to understand the global aerosol system. This complexity of the aerosol problem results from their short lifetime (1 week) and variable chemical composition. A new generation of satellites provides exciting opportunities to measure the global distribution of aerosols, distinguishing natural from anthropogenic aerosol and measuring their interaction with clouds and climate.

  4. Effects of trans-Eurasian transport of anthropogenic pollutants on surface ozone concentrations over China

    NASA Astrophysics Data System (ADS)

    Liu, J.; Li, X.; Mauzerall, D. L.; Emmons, L. K.; Horowitz, L. W.; Guo, Y.; Tao, S.

    2015-12-01

    Due to a lack of industrialization in Western China, surface air there was, until recently, believed to be relatively unpolluted. However, recent measurements and modeling studies have found high levels of ozone (O3) there. Based on the state-of-the-science global chemical transport model MOZART-4, we identify the origin, pathway, and mechanism of trans-Eurasian transport of air pollutants to Western China in 2000. MOZART-4 generally simulates well the observed surface O3 over inland areas of China. Simulations find surface ozone concentrations over Western China on average to be about 10 ppbv higher than Eastern China. Using sensitivity studies as well as a fully-tagged approach, we find that anthropogenic emissions from all Eurasian regions except China contribute 10-15 ppbv surface O3 over Western China, superimposed upon a 35-40 ppbv natural background. Transport from European anthropogenic sources to Northwestern China results in 2-6 ppbv O3 enhancements in spring and summer. Indian anthropogenic sources strongly influence O3 over the Tibetan Plateau during the summer monsoon. Transport of O3 originating from emissions in the Middle East occasionally reach Western China and increase surface ozone there by about 1-4 ppbv. These influences are of similar magnitude as trans-Pacific and transatlantic transport of O3 and its precursors, indicating the significance of trans-Eurasian ozone transport in hemispheric transport of air pollution. Our study further indicates that mitigation of anthropogenic emissions from Europe, the Indian subcontinent, and the Middle East could benefit public health and agricultural productivity in Western China.

  5. Effects of anthropogenic emissions on aerosol formation from isoprene and monoterpenes in the southeastern United States

    PubMed Central

    Xu, Lu; Guo, Hongyu; Boyd, Christopher M.; Klein, Mitchel; Bougiatioti, Aikaterini; Cerully, Kate M.; Hite, James R.; Kreisberg, Nathan M.; Knote, Christoph; Olson, Kevin; Koss, Abigail; Goldstein, Allen H.; Hering, Susanne V.; de Gouw, Joost; Baumann, Karsten; Lee, Shan-Hu; Nenes, Athanasios; Weber, Rodney J.; Ng, Nga Lee

    2015-01-01

    Secondary organic aerosol (SOA) constitutes a substantial fraction of fine particulate matter and has important impacts on climate and human health. The extent to which human activities alter SOA formation from biogenic emissions in the atmosphere is largely undetermined. Here, we present direct observational evidence on the magnitude of anthropogenic influence on biogenic SOA formation based on comprehensive ambient measurements in the southeastern United States (US). Multiple high-time-resolution mass spectrometry organic aerosol measurements were made during different seasons at various locations, including urban and rural sites in the greater Atlanta area and Centreville in rural Alabama. Our results provide a quantitative understanding of the roles of anthropogenic SO2 and NOx in ambient SOA formation. We show that isoprene-derived SOA is directly mediated by the abundance of sulfate, instead of the particle water content and/or particle acidity as suggested by prior laboratory studies. Anthropogenic NOx is shown to enhance nighttime SOA formation via nitrate radical oxidation of monoterpenes, resulting in the formation of condensable organic nitrates. Together, anthropogenic sulfate and NOx can mediate 43–70% of total measured organic aerosol (29–49% of submicron particulate matter, PM1) in the southeastern US during summer. These measurements imply that future reduction in SO2 and NOx emissions can considerably reduce the SOA burden in the southeastern US. Updating current modeling frameworks with these observational constraints will also lead to more accurate treatment of aerosol formation for regions with substantial anthropogenic−biogenic interactions and consequently improve air quality and climate simulations. PMID:25535345

  6. Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Kacarab, M.; Li, L.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Two surrogate reactive organic gas (ROG) mixtures were developed to create a controlled reactivity environment simulating different urban atmospheres with varying levels of anthropogenic (e.g. Los Angeles reactivity) and biogenic (e.g. Atlanta reactivity) influences. Traditional chamber experiments focus on the oxidation of one or two volatile organic compound (VOC) precursors, allowing the reactivity of the system to be dictated by those compounds. Surrogate ROG mixtures control the overall reactivity of the system, allowing for the incremental aerosol formation from an added VOC to be observed. The surrogate ROG mixtures were developed based on that used to determine maximum incremental reactivity (MIR) scales for O3 formation from VOC precursors in a Los Angeles smog environment. Environmental chamber experiments were designed to highlight the incremental aerosol formation in the simulated environment due to the addition of an added anthropogenic (aromatic) or biogenic (terpene) VOC. All experiments were conducted in the UC Riverside/CE-CERT dual 90m3 environmental chambers. It was found that the aerosol precursors behaved differently under the two altered reactivity conditions, with more incremental aerosol being formed in the anthropogenic ROG system than in the biogenic ROG system. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Data will be presented on aerosol properties (density, volatility, hygroscopicity) and bulk chemical composition in the gas and particle phases (from a SYFT Technologies selected ion flow tube mass spectrometer, SIFT-MS, and Aerodyne high resolution time of flight aerosol mass spectrometer, HR-ToF-AMS, respectively) comparing the two controlled reactivity systems and single precursor VOC/NOx studies. Incremental aerosol yield data at different controlled reactivities provide a novel and valuable insight in the attempt to extrapolate environmental chamber

  7. Effects of business-as-usual anthropogenic emissions on air quality

    NASA Astrophysics Data System (ADS)

    Pozzer, A.; Zimmermann, P.; Doering, U. M.; van Aardenne, J.; Tost, H.; Dentener, F.; Janssens-Maenhout, G.; Lelieveld, J.

    2012-04-01

    The atmospheric chemistry general circulation model EMAC has been used to estimate the impact of anthropogenic emission changes on global and regional air quality in recent and future years (2005, 2010, 2025 and 2050). The emission scenario assumes that population and economic growth largely determine energy and food consumption and consequent pollution sources with the current technologies ("business as usual"). This scenario is chosen to show the effects of not implementing legislation to prevent additional climate change and growing air pollution, other than what is in place for the base year 2005, representing a pessimistic (but feasible) future. By comparing with recent observations, it is shown that the model reproduces the main features of regional air pollution distributions though with some imprecisions inherent to the coarse horizontal resolution (~100 km) and simplified bottom-up emission input. To identify possible future hot spots of poor air quality, a multi pollutant index (MPI), suited for global model output, has been applied. It appears that East and South Asia and the Middle East represent such hotspots due to very high pollutant concentrations, although a general increase of MPIs is observed in all populated regions in the Northern Hemisphere. In East Asia a range of pollutant gases and fine particulate matter (PM2.5) is projected to reach very high levels from 2005 onward, while in South Asia air pollution, including ozone, will grow rapidly towards the middle of the century. Around the Arabian Gulf, where natural PM2.5 concentrations are already high (desert dust), ozone levels are expected to increase strongly. The per capita MPI (PCMPI), which combines demographic and pollutants concentrations projections, shows that a rapidly increasing number of people worldwide will experience reduced air quality during the first half of the 21st century. Following the business as usual scenario, it is projected that air quality for the global average

  8. Effects of business-as-usual anthropogenic emissions on air quality

    NASA Astrophysics Data System (ADS)

    Pozzer, A.; Zimmermann, P.; Doering, U. M.; van Aardenne, J.; Tost, H.; Dentener, F.; Janssens-Maenhout, G.; Lelieveld, J.

    2012-08-01

    The atmospheric chemistry general circulation model EMAC has been used to estimate the impact of anthropogenic emission changes on global and regional air quality in recent and future years (2005, 2010, 2025 and 2050). The emission scenario assumes that population and economic growth largely determine energy and food consumption and consequent pollution sources with the current technologies ("business as usual"). This scenario is chosen to show the effects of not implementing legislation to prevent additional climate change and growing air pollution, other than what is in place for the base year 2005, representing a pessimistic (but plausible) future. By comparing with recent observations, it is shown that the model reproduces the main features of regional air pollution distributions though with some imprecisions inherent to the coarse horizontal resolution (~100 km) and simplified bottom-up emission input. To identify possible future hot spots of poor air quality, a multi pollutant index (MPI), suited for global model output, has been applied. It appears that East and South Asia and the Middle East represent such hotspots due to very high pollutant concentrations, while a general increase of MPIs is observed in all populated regions in the Northern Hemisphere. In East Asia a range of pollutant gases and fine particulate matter (PM2.5) is projected to reach very high levels from 2005 onward, while in South Asia air pollution, including ozone, will grow rapidly towards the middle of the century. Around the Persian Gulf, where natural PM2.5 concentrations are already high (desert dust), ozone levels are expected to increase strongly. The population weighted MPI (PW-MPI), which combines demographic and pollutant concentration projections, shows that a rapidly increasing number of people worldwide will experience reduced air quality during the first half of the 21st century. Following this business as usual scenario, it is projected that air quality for the global

  9. Northern Hemisphere trends in carbon monoxide: effects of changing anthropogenic emissions and biomass burning

    NASA Astrophysics Data System (ADS)

    Novelli, P. C.; Petron, G.; Masarie, K.; Lang, P.; Granier, C.

    2010-12-01

    While the magnitude and direction of changes in tropospheric carbon monoxide (CO) during the past century are still debated; it is most likely that there have been extended periods of increase and decrease, overlaid with much shorter lived changes. The most compelling evidence for a long-term trend in the Northern Hemisphere (NH) comes from a comparison of column measurements determined above the Swiss Alps in the early 1950s and again in the mid-1980s which suggested an increase of ~1% yr-1. Quasi-continuous spectral measurements above Europe and western Russia show increasing column abundances in the 1970s through the mid-1980s, after which CO decreased at a similar rate through the mid-1990s. Several studies have shown declines in NH CO over the past two decades. Carbon monoxide has been measured in air samples collected by the NOAA Cooperative Air Sampling Network since 1988. The results provide a spatial and temporal picture of CO in the marine boundary layer which is used to identify zonal changes. The data suggest a long-term decrease in CO in the NH, with the greatest changes occurring in the 30-90 degree zonal band. Smaller decreases were found in the low Northern and Southern Hemispheres. The primary sources of CO in the NH are roughly evenly distributed between fossil fuel combustion and industrial emissions (FF), oxidation of methane and non-CH4 hydrocarbons, and biomass burning (BB); its major sink is OH. Here we examine how changes in FF and BB emissions have impacted CO in the lower troposphere. A strong decrease in anthropogenic emissions from Annex_1 countries in the early 1990s contributed to a significant decline in its abundance. Continuing declines in their emissions during the late 1990’s and 2000’s added to the downward trend despite increasing emissions from developing nations. The NH decrease in background CO during 1990-2005 (i.e. change determined without effects of the 1998/2003 fires) compares well with FF emissions inventories. Of

  10. Clinical review: The impact of noise on patients' sleep and the effectiveness of noise reduction strategies in intensive care units

    PubMed Central

    Xie, Hui; Kang, Jian; Mills, Gary H

    2009-01-01

    Excessive noise is becoming a significant problem for intensive care units (ICUs). This paper first reviews the impact of noise on patients' sleep in ICUs. Five previous studies have demonstrated such impacts, whereas six other studies have shown other factors to be more important. Staff conversation and alarms are generally regarded as the most disturbing noises for patients' sleep in ICUs. Most research in this area has focused purely on noise level, but work has been very limited on the relationships between sleep quality and other acoustic parameters, including spectrum and reverberation time. Sound-absorbing treatment is a relatively effective noise reduction strategy, whereas sound masking appears to be the most effective technique for improving sleep. For future research, there should be close collaboration between medical researchers and acousticians. PMID:19344486

  11. Effects of noise frequency on performance and annoyance for women and men

    NASA Technical Reports Server (NTRS)

    Key, K. F.; Payne, M. C., Jr.

    1981-01-01

    Effects of noise frequencies on both performance on a complex psychomotor task and annoyance were investigated for men (n = 30) and women (n = 30). Each subject performed a complex psychomotor task for 50 min in the presence of low-frequency noise, high-frequency noise, or ambient noise. Women and men learned the task at different rates. Little effect of noise was shown. Annoyance ratings were subsequently obtained from each subject for noises of various frequencies by the method of magnitude estimation. High-frequency noises were more annoying than low-frequency noises regardless of sex and immediate prior exposure to noise. Sex differences in annoyance did not occur. No direct relationship between learning to perform a complex task while exposed to noise and annoyance by that noise was demonstrated.

  12. Effects of noise frequency on performance and annoyance for women and men

    NASA Technical Reports Server (NTRS)

    Key, K. F.; Payne, M. C., Jr.

    1981-01-01

    Effects of noise frequencies on both performance on a complex psychomotor task and annoyance were investigated for men (n = 30) and women (n = 30). Each subject performed a complex psychomotor task for 50 min in the presence of low-frequency noise, high-frequency noise, or ambient noise. Women and men learned the task at different rates. Little effect of noise was shown. Annoyance ratings were subsequently obtained from each subject for noises of various frequencies by the method of magnitude estimation. High-frequency noises were more annoying than low-frequency noises regardless of sex and immediate prior exposure to noise. Sex differences in annoyance did not occur. No direct relationship between learning to perform a complex task while exposed to noise and annoyance by that noise was demonstrated.

  13. The effects of road traffic noise on mental performance.

    PubMed

    Alimohammadi, Iraj; Soltani, Raziyeh; Sandrock, Stephan; Azkhosh, Manouchehr; Gohari, Mahmood Reza

    2013-02-09

    Noise is one of the more widespread pollutions of road transportation system, which can cause deterioration in performance. This experimental study was designed to assess the effect of road traffic noise on performance with regard to extra/introversion and sex of participants. The personality trait of extra/introversion has been remarked as relevant factor to mental performance. Thirty six (26 males and 10 females) medical sciences students of Tehran University participated in the study. The students were placed in an unechoing room and performed the Cognitrone test from Vienna Test System in quiet condition and under road traffic noise (71 dBA). The results of this study pointed out that noise increased the percentage of sum of correct answers but had no effect on the speed of performance. Furthermore this study showed that performance was enhanced in extroverts (P=0.001) but no significant difference was found in introverts (P ≤0.05). The regression analysis revealed that extra/introversion was more important than sex to predict the performance parameters.

  14. The effects of road traffic noise on mental performance

    PubMed Central

    2013-01-01

    Background Noise is one of the more widespread pollutions of road transportation system, which can cause deterioration in performance. This experimental study was designed to assess the effect of road traffic noise on performance with regard to extra/introversion and sex of participants. The personality trait of extra/introversion has been remarked as relevant factor to mental performance. Results Thirty six (26 males and 10 females) medical sciences students of Tehran University participated in the study. The students were placed in an unechoing room and performed the Cognitrone test from Vienna Test System in quiet condition and under road traffic noise (71 dBA). The results of this study pointed out that noise increased the percentage of sum of correct answers but had no effect on the speed of performance. Furthermore this study showed that performance was enhanced in extroverts (P=0.001) but no significant difference was found in introverts (P ≤0.05). Conclusions The regression analysis revealed that extra/introversion was more important than sex to predict the performance parameters. PMID:23394722

  15. Physiological Stress Responses in Amphibian Larvae to Multiple Stressors Reveal Marked Anthropogenic Effects even below Lethal Levels.

    PubMed

    Burraco, Pablo; Gomez-Mestre, Ivan

    Natural and anthropogenic disturbances cause profound alterations in organisms, inducing physiological adjustments to avoid, reduce, or remedy the impact of disturbances. In vertebrates, the stress response is regulated via neuroendocrine pathways, including the hypothalamic-pituitary-interrenal axis that regulates the secretion of glucocorticoids. Glucocorticoids have cascading effects on multiple physiological pathways, affecting the metabolic rate, reactive oxygen species production, or immune system. Determining the extent to which natural and anthropogenic environmental factors induce stress responses in vertebrates is of great importance in ecology and conservation biology. Here we study the physiological stress response in spadefoot toad tadpoles (Pelobates cultripes) against three levels of a series of natural and anthropogenic stressors common to many aquatic systems: salinity (0, 6, and 9 ppt), herbicide (0, 1, and 2 mg/L acid equivalent of glyphosate), water acidity (pH 4.5, 7.0, and 9.5), predators (absent, native, and invasive), and temperature (21°, 25°, and 29°C). The physiological stress response was assessed examining corticosterone levels, standard metabolic rate, activity of antioxidant enzymes, oxidative cellular damage in lipids, and immunological status. We found that common stressors substantially altered the physiological state of tadpoles. In particular, salinity and herbicides cause dramatic physiological changes in tadpoles. Moreover, tadpoles reduced corticosterone levels in the presence of natural predators but did not do so against invasive predators, indicating a lack of innate recognition. Corticosterone and the antioxidant enzyme glutathione reductase were the most sensitive parameters to stress in this study. Anthropogenic perturbations of aquatic systems pose serious threats to larval amphibians even at nonlethal concentrations, judging from the marked physiological stress responses generated, and reveal the importance of

  16. Effects of night time road traffic noise—an overview of laboratory and field studies on noise dose and subjective noise sensitivity

    NASA Astrophysics Data System (ADS)

    Öhrström, E.; Rylander, R.; Björkman, M.

    1988-12-01

    This paper presents an overview of research on sleep and noise at the Department of Environmental Hygiene, University of Gothenburg. Different methods were developed to study primary and after effects of night time road traffic noise on sleep. Three one-week laboratory experiments were undertaken to study the relevance of different noise descriptors— Leq, maximum peak noise level and number of events with high peak noise levels—for sleep disturbance effects. The noise exposure was either single noise evenys or a continuous, even road traffic noise. It was concluded that Leq was not related to sleep disturbance effects. Peak noise levels were significantly related to subjective sleep quality and body movements. Results from a third continuing study showed that there is a threshold for effects of the number of single noise events on sleep quality. Habituation to noise among subjects with differing noise sensitivity was studied in a two-week experiment. A significant noise effect on subjective sleep quality was found among sensitive subjects only. No habituation was seen for the negative influence of noise on sleep quality, mood and performance. Long-term effects of road traffic noise were also investigated in a field survey among 106 individuals. This study revealed the presence of a decrease in sleep quality as well as psycho-social effects on tiredness and mood, together with increased reports of headaches and nervous stomach. As in the laboratory study, sensitive individuals were more affected by noise than less sensitive individuals.

  17. Economic Effects of Noise Abatement Regulations on the Helicopter Industry.

    DTIC Science & Technology

    1982-12-01

    are estimated. The effects an consumer utilization are also discussed. An appendix compares two independent research studies that used weight...helicopter by subsystem. This thesis proposes that if noise abatement regulations are iqposed on the helicopter industry without due consideration for future...abatement regu- lations on Sikorsky’s s-7S helicopter are estimated. The effects on consumer utilization are also discussed. kn appendix compares two

  18. Aircraft noise effects: An inter-disciplinary study of the effect of aircraft noise on man. Part 3: Supplementary analyses of the social-scientific portion of the study on aircraft noise conducted by the DFG

    NASA Technical Reports Server (NTRS)

    Schumer, R.

    1980-01-01

    Variables in a study of noise perception near the Munich-Reims airport are explained. The interactive effect of the stimulus (aircraft noise) and moderator (noise sensitivity) on the aircraft noise reaction (disturbance or annoyance) is considered. Methods employed to demonstrate that the moderator has a differencing effect on various stimulus levels are described. Results of the social-scientific portion of the aircraft noise project are compared with those of other survey studies on the problem of aircraft noise. Procedures for contrast group analysis and multiple classification analysis are examined with focus on some difficulties in their application.

  19. Effect of cigarette smoking on noise-induced hearing loss in workers exposed to occupational noise in China.

    PubMed

    Tao, Liyuan; Davis, Robert; Heyer, Nicholas; Yang, Qiuling; Qiu, Wei; Zhu, Liangliang; Li, Nan; Zhang, Hua; Zeng, Lin; Zhao, Yiming

    2013-01-01

    Excessive exposure to high noise level environments has the potential to cause noise-induced hearing loss (NIHL), and cigarette smoking has also been shown to have a potential adverse effect on hearing. The aim of this study was to determine whether smoking interacts with noise in the development of hearing loss, and if so, the extent of the contribution from smoking on NIHL. A cross-sectional study was designed to assess the effect of smoking on NIHL in 517 male workers (non-smokers: N = 199; smokers: N = 318) exposed to a high-level industrial noise environment in China. Shift-long temporal waveforms of the noise that workers were exposed to for evaluation of noise exposures, and audiometric threshold measures were obtained on all selected subjects. The subjects used hearing protection devices only within the last 1-2 years. The results suggest that smoking has an adverse effect on NIHL in workers exposed to high level industrial noise, i.e., the median high frequency hearing thresholds were significantly greater in smokers than non-smokers exposed to noise for more than 10 years. This effect was observed at 4.0 and 6.0 kHz. Smoking did not have an adverse effect on NIHL in workers exposed to noise less than 10 years. Multivariate regression analysis revealed that the odds ratio (OR) for high frequency hearing loss (i.e., hearing threshold greater than 40 dB at 4.0 kHz) were 1.94 for smokers in comparison to non-smokers. The results suggest that: (1) smokers have a higher risk of developing high frequency hearing loss than non-smokers with a similar occupational noise exposure, and (2) the interaction between cigarette smoking and high-level noise exposure may be additive. There is a need to develop and analyze a larger database of workers with well-documented exposures and smoking histories for better understanding of the effect of smoking on NIHL incurred from high-level industrial noise exposures. A better understanding of the role of smoking may lead to its

  20. The effect of airplane noise on the inhabitants of areas near Okecie Airport in Warsaw

    NASA Technical Reports Server (NTRS)

    Koszarny, Z.; Maziarka, S.; Szata, W.

    1981-01-01

    The state of health and noise annoyance among persons living in areas near Okecie airport exposed to various intensities of noise was evaluated. Very high annoyance effects of airplane noise of intensities over 100 dB (A) were established. A connection between the airplane noise and certain ailments complained about by the inhabitants was demonstrated.

  1. The effect of airplane noise on the inhabitants of areas near Okecie Airport in warsaw

    SciTech Connect

    Koszarny, Z.; Maziarka, S.; Szata, W.

    1981-05-01

    The state of health and noise annoyance among persons living in areas near Okecie airport exposed to various intensities of noise was evaluated. Very high annoyance effects of airplane noise of intensities over 100 dB (A) were established. A connection between the airplane noise and certain ailments complained about by the inhabitants was demonstrated.

  2. Effect of noise spectra and a listening task upon passenger annoyance in a helicopter interior noise environment

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Leatherwood, J. D.

    1979-01-01

    The effects of helicopter interior noise on passenger annoyance were studied. Both reverie and listening situations were studied as well as the relative effectiveness of several descriptors (i.e., overall sound pressure level, A-weighted sound pressure level, and speech interference level) for quantifying annoyance response for these situations. The noise stimuli were based upon recordings of the interior noise of a civil helicopter research aircraft. These noises were presented at levels ranging from approximately 68 to 86 dB(A) with various gear clash tones selectively attenuated to give a range of spectra. Results indicated that annoyance during a listening condition is generally higher than annoyance during a reverie condition for corresponding interior noise environments. Attenuation of the planetary gear clash tone results in increases in listening performance but has negligible effect upon annoyance for a given noise level. The noise descriptor most effective for estimating annoyance response under conditions of reverie and listening situations is shown to be the A-weighted sound pressure level.

  3. Psycho-social effects of traffic noise exposure

    NASA Astrophysics Data System (ADS)

    Öhrström, E.

    1991-12-01

    In this paper a study of psycho-social effects of exposure to high levels of road traffic noise is presented. A questionnaire was constructed to evaluate not only annoyance reactions and sleep disturbance effects of noise, but also more long-term effects on psycho-social well-being (PSW). PSW was evaluated by 26 questions concerning depression, relaxation, activity, passivity, general well-being and social orientation. The postal questionnaire was answered by 151 persons in a quiet city area and 97 persons in an area exposed to an Leq level of 72 dB(A). The results showed that a higher proportion of those who lived in the noisy area in apartments with windows facing the street more often felt depressed. Those who had windows facing the courtyard, in the noisy area, however, were not more depressed that those who lived in the quiet area. Methodological difficulties in this type of study are also discussed in the paper.

  4. Effect of Contralateral Noise on Acoustic Reflex Latency Measures.

    PubMed

    Prabhu, Prashanth; Divyashree, Koratagere Narayanaswamy; Neeraja, Raju; Akhilandeshwari, Sivaswami

    2015-12-01

    The present study was conducted to determine the effect of contralateral broadband noise on acoustic reflex latency (ARL). Acoustic reflex latency changes for 10 and 90% on- and off-time acoustic reflexes with contralateral broadband noise were measured in 30 adults with normal hearing. The results of the study demonstrate that there was a latency prolongation for reflex on-time (10 and 90%) and latency reduction for reflex off-time (10 and 90%). This effect was seen for 500, 1000, and 2000 Hz reflex-eliciting signals. The results also showed that there was no effect of gender on latency changes in acoustic reflexes. Latency changes may explain efferent auditory system mechanisms used for the protection of the cochlea and improvement in speech perception. Thus, contralateral changes of ARL can serve as an additional tool to assess the efferent system functioning.

  5. Effect of Microjet Injection on Supersonic Jet Noise

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.; Podboy, G. G.

    2010-01-01

    The effect of microjet (jet) injection on the noise from supersonic jets is investigated. Three convergent-divergent (C-D) nozzles and one convergent nozzle, all having the same exit diameters, are used in the study. The jets are injected perpendicular to the primary jet close to the nozzle lip from six equally-spaced ports having a jet-to-primary-jet diameter ratio of 0.0054. Effects in the over-expanded, fully expanded as well as underexpanded flow regimes are explored. Relative to the effect on subsonic jets, larger reductions in the overall sound pressure level (OASPL) are achieved in most supersonic conditions. The largest reductions are typically associated with suppression of screech and transonic tones. For a shock-free, fully expanded case, the OASPL reductions achieved are comparable to that in the subsonic case; the same correlation, found for subsonic jet noise reduction at shallow observation angle, applies.

  6. The effects of road traffic noise and meaningful irrelevant speech on different memory systems.

    PubMed

    Hygge, Staffan; Boman, Eva; Enmarker, Ingela

    2003-02-01

    To explore why noise has reliable effects on delayed recall in a certain text-reading task, this episodic memory task was employed with other memory tests in a study of road traffic noise and meaningful but irrelevant speech. Context-dependent memory was tested and self-reports of affect were taken. Participants were 96 high school students. The results showed that both road traffic noise and meaningful irrelevant speech impaired recall of the text. Retrieval in noise from semantic memory was also impaired. Attention was impaired by both noise sources, but attention did not mediate the noise effects on episodic memory. Recognition was not affected by noise. Context-dependent memory was not shown. The lack of mediation by attention, and road traffic noise being as harmful as meaningful irrelevant speech, are discussed in relation to where in the input/storing/output sequence noise has its effect and what the distinctive feature of the disturbing noise is.

  7. Individual Letter Contrast Thresholds: Effect of Object Frequency and Noise

    PubMed Central

    Hall, Cierra; Wang, Shu; McAnany, J. Jason

    2015-01-01

    Purpose To compare differences in contrast threshold among individual Sloan letters presented in additive white luminance noise and in the absence of noise. Methods Contrast threshold for letter identification was measured for 3 visually normal subjects (ages 22, 25, 34 years) using letters from the Sloan set (C, D, H, K, N, O, R, S, V, Z). The letter size was equivalent to 1.5 log MAR and the letters were either unfiltered or band-pass filtered to limit the object frequency content (cycles-per-letter; cpl) to a one-octave wide band centered at 1.25, 2.5, 5, and 10 cpl. Letters were presented for an unlimited duration against a uniform adapting field or in the presence of additive white luminance noise. Contrast threshold for each letter was determined using a 10 alternative forced choice interleaved staircase procedure. Results For standard unfiltered Sloan letters presented against a uniform field, contrast threshold for individual letters differed by as much as a factor of 1.5, consistent with a previous report. When measured in luminance noise, the individual letters differed by as much as a factor of 1.8. Bandpass filtering the letters to include only low object frequencies increased the differences in contrast threshold among the individual letters (approximately a factor of 3) compared to unfiltered letters and letters filtered into high object frequency bands. Conclusions The addition of white luminance noise had relatively small effects on inter-letter contrast threshold differences, whereas band-pass filtering had large effects on inter-letter threshold differences, greatly increasing variation among the letters that contained only low object frequencies. Letters that contain only high object frequencies may be useful in the design of letter charts because the inter-letter threshold differences are relatively small for these optotypes and the object frequency information mediating identification is known. PMID:26540471

  8. Laser phase noise effects on the dynamics of optomechanical resonators

    SciTech Connect

    Phelps, Gregory A.; Meystre, Pierre

    2011-06-15

    We investigate theoretically the influence of laser phase noise on the cooling and heating of a generic cavity optomechanical system. We derive the back-action damping and heating rates and the mechanical frequency shift of the radiation-pressure-driven oscillating mirror, and derive the minimum phonon occupation number for small laser linewidths. We find that, in practice, laser phase noise does not pose serious limitations to ground-state cooling. Additionally, we explore the regime of parametric amplification where coherent oscillations of the mirror are realizable. It is found that heating from laser phase noise is of significance and can cause the onset of instabilities. We then consider the effects of laser phase noise in a parametric cavity driving scheme that minimizes the back-action heating of one of the quadratures of the mechanical oscillator motion. Laser linewidths, narrow compared to the decay rate of the cavity field, do not pose any significant problems in an experimental setting, but broader linewidths limit the practicality of this back-action evasion method.

  9. Kramers problem for a dimer: Effect of noise correlations

    NASA Astrophysics Data System (ADS)

    Singh, R. K.

    2017-04-01

    The Kramers problem for a dimer in a bistable piecewise linear potential is studied in the presence of correlated noise processes. The effect of such a correlation is to redistribute the thermal power between the dynamical degrees of freedom, and this leads to significant deviations in the dynamics of the system from the case of independent noise processes. The distribution of first passage times from one minima to the basin of attraction of the other minima is found to have exponentially decaying tails with the parameter dependent on the amount of correlation and the coupling between the particles. The strong coupling limit of the problem is analyzed using adiabatic elimination, where it is found that the initial probability density relaxes towards a stationary value on the same time scale as the mean escape time when the noise intensity of the system is low. For higher noise fluctuations, the relaxation towards the stationary state is slower in comparison to escape times. In the extreme limit of perfect anticorrelation, the random dynamical system behaves as a deterministic system in a steady state in which the center of mass starting from the unstable maxima moves down the hill and gets trapped in the potential minima. The implications for polymer dynamics in a potential are discussed.

  10. Effect of contralateral white noise masking on the mismatch negativity.

    PubMed

    Salo, S K; Lang, A H; Salmivalli, A J

    1995-01-01

    Mismatch negativity (MMN), an auditive event-related potential (ERP) component, evoked by deviant stimuli in a homogeneous stream of standard stimuli was studied in a unilateral stimulation and contralateral white noise masking condition. Eleven subjects (Ss) with normal hearing (aged 20-35 years) were examined using sine tone stimuli (70 dB HL, interstimulus interval 300 ms, duration 40 ms with 5 ms rise and fall times). Three blocks of standard (std)/deviant (dev) series of stimuli were used: std 500/dev 600 Hz, std 2000/dev 1900 Hz, and std 2000/dev 1600 Hz. The first block was repeated for another group of 11 Ss with normal hearing (aged 17-27 years). The MMN was analysed from the difference curves recorded at Fz, Cz and Pz. The stimuli were delivered unilaterally, either with or without 50 dB effective masking level white noise to the contralateral ear. The MMN amplitude attenuated significantly when contralateral masking was used. In addition, there was interaction between noise masking and the stimulated ear. The MMN latencies were not affected by white noise masking.

  11. Effects of noise reduction on AM and FM perception.

    PubMed

    Ives, D Timothy; Calcus, Axelle; Kalluri, Sridhar; Strelcyk, Olaf; Sheft, Stanley; Lorenzi, Christian

    2013-02-01

    The goal of noise reduction (NR) algorithms in digital hearing aid devices is to reduce background noise whilst preserving as much of the original signal as possible. These algorithms may increase the signal-to-noise ratio (SNR) in an ideal case, but they generally fail to improve speech intelligibility. However, due to the complex nature of speech, it is difficult to disentangle the numerous low- and high-level effects of NR that may underlie the lack of speech perception benefits. The goal of this study was to better understand why NR algorithms do not improve speech intelligibility by investigating the effects of NR on the ability to discriminate two basic acoustic features, namely amplitude modulation (AM) and frequency modulation (FM) cues, known to be crucial for speech identification in quiet and in noise. Here, discrimination of complex, non-linguistic AM and FM patterns was measured for normal hearing listeners using a same/different task. The stimuli were generated by modulating 1-kHz pure tones by either a two-component AM or FM modulator with patterns changed by manipulating component phases. Modulation rates were centered on 3 Hz. Discrimination of AM and FM patterns was measured in quiet and in the presence of a white noise that had been passed through a gammatone filter centered on 1 kHz. The noise was presented at SNRs ranging from -6 to +12 dB. Stimuli were left as such or processed via an NR algorithm based on the spectral subtraction method. NR was found to yield small but systematic improvements in discrimination for the AM conditions at favorable SNRs but had little effect, if any, on FM discrimination. A computational model of early auditory processing was developed to quantify the fidelity of AM and FM transmission. The model captured the improvement in discrimination performance for AM stimuli at high SNRs with NR. However, the model also predicted a relatively small detrimental effect of NR for FM stimuli in contrast with the average

  12. Limited Effect of Anthropogenic Nitrogen Oxides on Secondary Organic Aerosol Formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Knote, C. J.; Tilmes, S.; Emmons, L. K.; Lamarque, J. F.; Yu, P.

    2014-12-01

    Globally secondary organic aerosol (SOA) is mostly formed from biogenic vegetation emissions and as such is regarded as natural aerosol that cannot be reduced by emission control legislation. However, recent research implies that human activities facilitate SOA formation by affecting the amount of precursor emission, the chemical processing and the partitioning into the aerosol phase. Among the multiple human influences, nitrogen oxides (NO + NO2 = NOx) have been assumed to play a critical role in the chemical formation of low volatile compounds. The goal of this study is to improve the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-Chem) by implementing an updated 4-product Volatility Basis Set (VBS) scheme, and apply it to investigate the impact of anthropogenic NOx on SOA. We first compare three different SOA parameterizations: a 2-product model and the updated VBS model both with and without a SOA aging parameterization. Secondly we evaluate predicted organic aerosol amounts against surface measurement from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network and Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns. We then perform sensitivity experiments to examine how the SOA loading responds to a 50% reduction in anthropogenic NOx in different regions. We find limited SOA reductions of -2.3%, -5.6% and -4.0% for global, southeastern U.S. and Amazon NOx perturbations, respectively. To investigate the chemical processes in more detail, we also use a simplified box model with the same gas-phase chemistry and gas-aerosol partitioning mechanism as in CAM4-Chem to examine the SOA yields dependence on initial precursor emissions and background NOx level. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- versus high-NOx pathways, OH versus NO3-initiated oxidation) and to offsetting

  13. The effect of anthropogenic emissions corrections on the seasonal cycle of atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Brooks, B. J.; Hoffman, F. M.; Mills, R. T.; Erickson, D. J.; Blasing, T. J.

    2009-12-01

    A previous study (Erickson et al. 2008) approximated the monthly global emission estimates of anthropogenic CO2 by applying a 2-harmonic Fourier expansion with coefficients as a function of latitude to annual CO2 flux estimates derived from United States data (Blasing et al. 2005) that were extrapolated globally. These monthly anthropogenic CO2 flux estimates were used to model atmospheric concentrations using the NASA GEOS-4 data assimilation system. Local variability in the amplitude of the simulated CO2 seasonal cycle were found to be on the order of 2-6 ppmv. Here we used the same Fourier expansion to seasonally adjust the global annual fossil fuel CO2 emissions from the SRES A2 scenario. For a total of four simulations, both the annual and seasonalized fluxes were advected in two configurations of the NCAR Community Atmosphere Model (CAM) used in the Carbon-Land Model Intercomparison Project (C-LAMP). One configuration used the NCAR Community Land Model (CLM) coupled with the CASA‧ (carbon only) biogeochemistry model and the other used CLM coupled with the CN (coupled carbon and nitrogen cycles) biogeochemistry model. All four simulations were forced with observed sea surface temperatures and sea ice concentrations from the Hadley Centre and a prescribed transient atmospheric CO2 concentration for the radiation and land forcing over the 20th century. The model results exhibit differences in the seasonal cycle of CO2 between the seasonally corrected and uncorrected simulations. Moreover, because of differing energy and water feedbacks between the atmosphere model and the two land biogeochemistry models, features of the CO2 seasonal cycle were different between these two model configurations. This study reinforces previous findings that suggest that regional near-surface atmospheric CO2 concentrations depend strongly on the natural sources and sinks of CO2, but also on the strength of local anthropogenic CO2 emissions and geographic position. This work further

  14. Potential effects of anthropogenic nitrogen on northern Indian Ocean nitrous oxide emissions

    NASA Astrophysics Data System (ADS)

    Zamora, L. M.; Suntharalingam, P.; Bange, H. W.; Bikkina, S.; Resplandy, L.; Sarin, M.; Schmidtko, S.; Seitzinger, S.; Singh, A.

    2016-02-01

    The North Indian Ocean (Arabian Sea + Bay of Bengal) accounts for 20-30% of the oceanic emissions of the greenhouse gas, nitrous oxide (N2O). The marine N2O cycle in the suboxic and anoxic waters of this region is very sensitive to relatively small shifts in ambient oxygen (O2); as O2 decreases, N2O production is progressively enhanced and subject to non-linear nitrogen (N) cycle dynamics. Thus, small, sustained changes in local O2 levels (e.g., < 5-10 mmol L-1) may result in detectable impacts on N2O emissions from the North Indian Ocean. Some recent data suggest that O2 may be declining in the already O2-impoverished Arabian Sea. While the reasons for these possible O2 declines are not fully understood, increasing anthropogenic N inputs from atmospheric and riverine sources likely contribute. In this study we bring together a combination of atmospheric deposition models, in situ measurements, and output from the NEWS riverine model to evaluate recent changes in nitrogen nutrient input to the Arabian Sea. We estimate that there has been a twofold increase in N loading from anthropogenic atmospheric deposition and river runoff to the North Indian Ocean during recent decades. To better understand how anthropogenic N increases might affect regional N2O emissions, we also present analysis of historical N2O and O2 measurements from the North Indian Ocean along with estimates of O2 and N2O fluxes from a regional marine biogeochemical model. We find that as in the Arabian Sea, Bay of Bengal O2 is also likely decreasing. However, due to the paucity of data, we are not yet able to estimate the role of anthropogenic N or how these changes might affect Bay of Bengal N2O emissions. While uncertainties are also high in the Arabian Sea, our preliminary results suggest that increases in atmospheric N deposition are enhancing regional N2O production.

  15. Effect of anthropogenic activities on the water quality of Amala and Nyangores tributaries of River Mara in Kenya.

    PubMed

    Nyairo, Wilfrida Nyanduko; Owuor, Philip Okinda; Kengara, Fredrick Orori

    2015-11-01

    Mau Forest in the upper reaches of the Mara River basin has recently undergone increased forest destruction followed by human settlement and agricultural activities. These anthropogenic activities may be contributing nutrients and heavy metals, ultimately polluting the river water and eventually Lake Victoria water hence damaging these aquatic ecosystems. This study sought to establish the effect of anthropogenic activities and season on the water quality of the Amala and Nyangores tributaries of the River Mara in Kenya. Pristine springs in the Mau Forest were used as reference sites. Water samples were analyzed for pH, temperature, conductivity, nutrients, selected heavy metals, and selenium. The mean range of the parameters measured from sites along the tributaries was pH 5.44-7.48 and that for conductivity was 20-99 μS/cm while the mean range of nutrient levels (μg/L) was 80-443 (NO3--N), 21.7-82.7 (NH4+-N), 11.9-65.0 (soluble reactive phosphorous), and 51-490 (total phosphorous). The mean range for heavy metals and selenium (in μg/L) from sites along the tributaries were 6.56-37.6 (Cu), 0.26-4.97 (Cd), 13.9-213 (Zn), 0.35-3.14 (Cr), 0.19-5.53 (Mn), 1.90-9.62 (Pb), and 0.21-4.50 (Se). The results indicated a significant difference (p≤0.05) between the reference sites and the different sampling sites, indicating that anthropogenic activities were impacting the quality of water in the two tributaries. Although most of the parameters were within the WHO (2004), USEPA (2014) and NEMA (2006) acceptable limits for surface waters, they were above the permissible levels for domestic use. Moreover, the levels of nutrients, heavy metals, and selenium were significantly higher in the wet season than in the dry season, further indicating that anthropogenic activities are causing a disturbance in the aquatic system. Therefore, further anthropogenic activities should be checked and limited so as to conserve the ecosystem.

  16. Modelling the ocean site effect on seismic noise body waves

    NASA Astrophysics Data System (ADS)

    Gualtieri, L.; Stutzmann, E.; Farra, V.; Capdeville, Y.; Schimmel, M.; Ardhuin, F.; Morelli, A.

    2014-05-01

    Secondary microseismic noise is generated by non-linear interactions between ocean waves at the ocean surface. We present here the theory for computing the site effect of the ocean layer upon body waves generated by noise sources distributed along the ocean surface. By defining the wavefield as the superposition of plane waves, we show that the ocean site effect can be described as the constructive interference of multiply reflected P waves in the ocean that are then converted to either P or SV waves at the ocean-crust interface. We observe that the site effect varies strongly with period and ocean depth, although in a different way for body waves than for Rayleigh waves. We also show that the ocean site effect is stronger for P waves than for S waves. We validate our computation by comparing the theoretical noise body wave sources with the sources inferred from beamforming analysis of the three seismogram components recorded by the Southern California Seismic Network. We use rotated traces for the beamforming analysis, and we show that we clearly detect P waves generated by ocean gravity wave interactions along the track of typhoon Ioke (2006 September). We do not detect the corresponding SV waves, and we demonstrate that this is because their amplitude is too weak.

  17. A Model for Shear Layer Effects on Engine Noise Radiation

    NASA Technical Reports Server (NTRS)

    Nark, Douglas M.; Farassat, F.; Pope, D. Stuart; Vatsa, V.

    2004-01-01

    Prediction of aircraft engine noise is an important aspect of addressing the issues of community noise and cabin noise control. The development of physics based methodologies for performing such predictions has been a focus of Computational Aeroacoustics (CAA). A recent example of code development in this area is the ducted fan noise propagation and radiation code CDUCT-LaRC. Included within the code is a duct radiation model that is based on the solution of FfowcsWilliams-Hawkings (FW-H) equation with a penetrable data surface. Testing of this equation for many acoustic problems has shown it to provide generally better results than the Kirchhoff formula for moving surfaces. Currently, the data surface is taken to be the inlet or exhaust plane for inlet or aft-fan cases, respectively. While this provides reasonable results in many situations, these choices of data surface location lead to a few limitations. For example, the shear layer between the bypass ow and external stream can refract the sound waves radiated to the far field. Radiation results can be improved by including this effect, as well as the rejection of the sound in the bypass region from the solid surface external to the bypass duct surrounding the core ow. This work describes the implementation, and possible approximation, of a shear layer boundary condition within CDUCT-LaRC. An example application also illustrates the improvements that this extension offers for predicting noise radiation from complex inlet and bypass duct geometries, thereby providing a means to evaluate external treatments in the vicinity of the bypass duct exhaust plane.

  18. Laser phase noise effects on the dynamics of optomechanical resonators

    NASA Astrophysics Data System (ADS)

    Phelps, Gregory; Meystre, Pierre

    2011-05-01

    We present a theoretical analysis of the effects of laser phase noise on the sideband cooling of opto-mechanical oscillators, demonstrating how it limits the minimum occupation number of the phonon mode being cooled and how it modifies optical cooling rate and mechanical frequency shift of the mechanical element. We also comment on the effects of laser phase noise on coherent oscillations of the mechanical element in the blue detuned regime and on the back-action evasion detection method where an additional drive is used to prevent heating of one quadrature of motion of the oscillator. This work was supported by the US Office of Naval Research, the US National Science Foundation, the US Army Research Office and the DARPA ORCHID program through a grant from AFOSR.

  19. Effect of Anthropogenic Landscape Features on Population Genetic Differentiation of Przewalski's Gazelle: Main Role of Human Settlement

    PubMed Central

    Yang, Ji; Jiang, Zhigang; Zeng, Yan; Turghan, Mardan; Fang, Hongxia; Li, Chunwang

    2011-01-01

    Anthropogenic landscapes influence evolutionary processes such as population genetic differentiation, however, not every type of landscape features exert the same effect on a species, hence it is necessary to estimate their relative effect for species management and conservation. Przewalski's gazelle (Procapra przewalskii), which inhabits a human-altered area on Qinghai-Tibet Plateau, is one of the most endangered antelope species in the world. Here, we report a landscape genetic study on Przewalski's gazelle. We used skin and fecal samples of 169 wild gazelles collected from nine populations and thirteen microsatellite markers to assess the genetic effect of anthropogenic landscape features on this species. For comparison, the genetic effect of geographical distance and topography were also evaluated. We found significant genetic differentiation, six genetic groups and restricted dispersal pattern in Przewalski's gazelle. Topography, human settlement and road appear to be responsible for observed genetic differentiation as they were significantly correlated with both genetic distance measures [FST/(1−FST) and F′ST/(1−F′ST)] in Mantel tests. IBD (isolation by distance) was also inferred as a significant factor in Mantel tests when genetic distance was measured as FST/(1−FST). However, using partial Mantel tests, AICc calculations, causal modeling and AMOVA analysis, we found that human settlement was the main factor shaping current genetic differentiation among those tested. Altogether, our results reveal the relative influence of geographical distance, topography and three anthropogenic landscape-type on population genetic differentiation of Przewalski's gazelle and provide useful information for conservation measures on this endangered species. PMID:21625459

  20. ASSESSING THE EFFECTS OF NATURAL AND ANTHROPOGENIC STRESSORS IN THE POTOMAC ESTUARY: IMPLICATIONS FOR LONG-TERM MONITORING

    EPA Science Inventory

    Ecological conditions in the Potomac Estuary are affected by a variety of natural and anthropogenic stressors. Natural climatic factors combined with anthropogenic activities affect fluxes of material through Potomac River watersheds and cause changes in ecological conditions in ...

  1. A review of crustacean sensitivity to high amplitude underwater noise: Data needs for effective risk assessment in relation to UK commercial species.

    PubMed

    Edmonds, Nathan J; Firmin, Christopher J; Goldsmith, Denise; Faulkner, Rebecca C; Wood, Daniel T

    2016-07-15

    High amplitude anthropogenic noise is associated with adverse impacts among a variety of organisms but detailed species-specific knowledge is lacking in relation to effects upon crustaceans. Brown crab (Cancer pagurus), European lobster (Homarus gammarus) and Norway lobster (Nephrops norvegicus) together represent the most valuable commercial fishery in the UK (Defra, 2014). Critical evaluation of literature reveals physiological sensitivity to underwater noise among N. norvegicus and closely related crustacean species, including juvenile stages. Current evidence supports physiological sensitivity to local, particle motion effects of sound production in particular. Derivation of correlative relationships between the introduction of high amplitude impulsive noise and crustacean distribution/abundance is hindered by the coarse resolution of available data at the present time. Future priorities for research are identified and argument for enhanced monitoring under current legislative frameworks outlined. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  2. Effect of vorticity distribution on the blades on fan noise

    NASA Astrophysics Data System (ADS)

    Koscso, Gabor

    Tests have been performed to determine the connection between noise emission of radial flow fans, impellers, with different inlet design, and vorticity distribution on the blades. An inlet cone protruding into the impeller was found to reduce significantly the radiated sound power level. Measurements showed that for the tested impellers about the duty point corresponding to maximum efficiency, vorticity distribution on the blades has little effect on the sound power level.

  3. The effect of system nonlinearities on system noise statistics

    NASA Technical Reports Server (NTRS)

    Robinson, L. H., Jr.

    1971-01-01

    The effects are studied of nonlinearities in a baseline communications system on the system noise amplitude statistics. So that a meaningful identification of system nonlinearities can be made, the baseline system is assumed to transmit a single biphase-modulated signal through a relay satellite to the receiving equipment. The significant nonlinearities thus identified include square-law or product devices (e.g., in the carrier reference recovery loops in the receivers), bandpass limiters, and traveling wave tube amplifiers.

  4. The effect of anthropogenic activities to the decrease of water quality

    NASA Astrophysics Data System (ADS)

    Sidabutar, N. V.; Namara, I.; Hartono, D. M.; Soesilo, T. E. B.

    2017-05-01

    The raw water in Jakarta is supplied from Jatiluhur Dam, which is distributed pass through West Tarum Canal with an open canal about 70 km long. This water quality does not meet the standard set by the government and heavily polluted by anthropogenic activities along its river. This research uses a quantitative research approach with the mix-method. This research did an in-depth interview with inhabitants along the riverbank about their daily activity. The water along the riverbank is polluted by anthropogenic activities, such as: first: domestic activities (washing, cooking, and bathing), second: littering into the river, and third: discharging waste water from households into the river. This present research measures water quality for parameters pH, temperature, Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), Total Dissolved Solid (TDS), Total Suspended Solid (TSS), and Fecal coliform. In this social segment, it is shown that pH, DO, TDS and Fecal coliformin the downstream part are worse than in the upstream.

  5. The effects of noise exposure and musical training on suprathreshold auditory processing and speech perception in noise.

    PubMed

    Yeend, Ingrid; Beach, Elizabeth Francis; Sharma, Mridula; Dillon, Harvey

    2017-09-01

    Recent animal research has shown that exposure to single episodes of intense noise causes cochlear synaptopathy without affecting hearing thresholds. It has been suggested that the same may occur in humans. If so, it is hypothesized that this would result in impaired encoding of sound and lead to difficulties hearing at suprathreshold levels, particularly in challenging listening environments. The primary aim of this study was to investigate the effect of noise exposure on auditory processing, including the perception of speech in noise, in adult humans. A secondary aim was to explore whether musical training might improve some aspects of auditory processing and thus counteract or ameliorate any negative impacts of noise exposure. In a sample of 122 participants (63 female) aged 30-57 years with normal or near-normal hearing thresholds, we conducted audiometric tests, including tympanometry, audiometry, acoustic reflexes, otoacoustic emissions and medial olivocochlear responses. We also assessed temporal and spectral processing, by determining thresholds for detection of amplitude modulation and temporal fine structure. We assessed speech-in-noise perception, and conducted tests of attention, memory and sentence closure. We also calculated participants' accumulated lifetime noise exposure and administered questionnaires to assess self-reported listening difficulty and musical training. The results showed no clear link between participants' lifetime noise exposure and performance on any of the auditory processing or speech-in-noise tasks. Musical training was associated with better performance on the auditory processing tasks, but not the on the speech-in-noise perception tasks. The results indicate that sentence closure skills, working memory, attention, extended high frequency hearing thresholds and medial olivocochlear suppression strength are important factors that are related to the ability to process speech in noise. Crown Copyright © 2017. Published by

  6. Combined effect of noise and vibration produced by high-speed trains on annoyance in buildings.

    PubMed

    Lee, Pyoung Jik; Griffin, Michael J

    2013-04-01

    The effects of noise and vibration on annoyance in buildings during the passage of a nearby high-speed train have been investigated in a laboratory experiment with recorded train noise and 20 Hz vibration. The noises included the effects of two types of façade: windows-open and windows-closed. Subjects were exposed to six levels of noise and six magnitudes of vibration, and asked to rate annoyance using an 11-point numerical scale. The experiment consisted of four sessions: (1) evaluation of noise annoyance in the absence of vibration, (2) evaluation of total annoyance from simultaneous noise and vibration, (3) evaluation of noise annoyance in the presence of vibration, and (4) evaluation of vibration annoyance in the absence of noise. The results show that vibration did not influence ratings of noise annoyance, but that total annoyance caused by combined noise and vibration was considerably greater than the annoyance caused by noise alone. The noise annoyance and the total annoyance caused by combined noise and vibration were associated with subject self-ratings of noise sensitivity. Two classical models of total annoyance due to combined noise sources (maximum of the single source annoyance or the integration of individual annoyance ratings) provided useful predictions of the total annoyance caused by simultaneous noise and vibration.

  7. Assessing the effects of noise abatement measures on health risks: A case study in Istanbul

    SciTech Connect

    Ongel, Aybike; Sezgin, Fatih

    2016-01-15

    In recent decades, noise pollution caused by industrialization and increased motorization has become a major concern around the world because of its adverse effects on human well-being. Therefore, transportation agencies have been implementing noise abatement measures in order to reduce road traffic noise. However, limited attention is given to noise in environmental assessment of road transportation systems. This paper presents a framework for a health impact assessment model for road transportation noise emissions. The model allows noise impacts to be addressed with the health effects of air pollutant and greenhouse gas emissions from road transportation. The health damages assessed in the model include annoyance, sleep disturbance, and cardiovascular disease in terms of acute myocardial infarction. The model was applied in a case study in Istanbul in order to evaluate the change in health risks from the implementation of noise abatement strategies. The noise abatement strategies evaluated include altering pavement surfaces in order to absorb noise and introducing speed limits. It was shown that significant improvements in health risks can be achieved using open graded pavement surfaces and introducing speed limits on highways. - Highlights: • Transportation noise has a significant effect on health. • Noise should be included in the environmental assessment of transportation systems. • Traffic noise abatement measures include noise reducing pavements and speed limits. • Noise abatement measures help reduce the health risks of transportation noise. • Speed limit reduction on uncongested roads is an effective way to reduce health risks.

  8. Effects of shift work on noise-induced hearing loss.

    PubMed

    Chou, Yu-Fung; Lai, Jim-Shoung; Kuo, Hsien-Wen

    2009-01-01

    Evidence has accumulated concerning the adverse effects of noise on hearing acuity, but it is not clear whether working shifts may decelerate the effects of hearing loss. The objective of this study is to assess the effects of shift work on hearing loss in a noisy work environment. A sample of 218 male workers recruited at a semiconductor factory with no known occupational hazards that affected hearing acuity other than noise was chosen. The subjects worked either in an eight-hour or 12-hour shift. A standardized audiometric procedure was performed by a qualified audiologist to measure pure-tone hearing thresholds at 0.5 kHz, 1 kHz, 2 kHz, 3 kHz, 4 kHz, 6 kHz and 8 kHz in both ears. Using multiple linear regression adjusted for age, smoking habits, and work duration, the results showed that the severity of hearing loss in both ears was significantly lower in subjects who worked a 12-hour shift. In conclusion, working a 12-hour shift followed by a day off is best for workers and hearing protection should be provided in high noise areas.

  9. Effect of Free Jet on Refraction and Noise

    NASA Technical Reports Server (NTRS)

    Khavaran, Abbas; Georgiadis, Nicholas J.; Bridges, James E.; Dippold, Vance F., III

    2005-01-01

    This article investigates the role of a free jet on the sound radiated from a jet. In particular, the role of an infinite wind tunnel, which simulates the forward flight condition, is compared to that of a finite wind tunnel. The second configuration is usually used in experiments, where the microphones are located in a static ambient medium far outside the free jet. To study the effect of the free jet on noise, both propagation and source strength need to be addressed. In this work, the exact Green's function in a locally parallel flow is derived for a simulated flight case. Numerical examples are presented that show a reduction in the magnitude of the Green's function in the aft arc and an increase in the forward arc for the simulated flight condition. The effect of finite wind tunnel on refraction is sensitive to the source location and is most pronounced in the aft arc. A Reynolds-averaged Navier-Stokes solution (RANS) yields the required mean flow and turbulence scales that are used in the jet mixing noise spectrum calculations. In addition to the sound/flow interaction, the separate effect of source strength and elongation of the noise-generating region of the jet in a forward flight is studied. Comparisons are made with experiments for the static and finite tunnel cases. Finally, the standard free-jet shear corrections that convert the finite wind tunnel measurements to an ideal wind tunnel arrangement are evaluated.

  10. Effects of noise on the performance of a memory decision response task

    NASA Technical Reports Server (NTRS)

    Lawton, B. W.

    1972-01-01

    An investigation has been made to determine the effects of noise on human performance. Fourteen subjects performed a memory-decision-response task in relative quiet and while listening to tape recorded noises. Analysis of the data obtained indicates that performance was degraded in the presence of noise. Significant increases in problem solution times were found for impulsive noise conditions as compared with times found for the no-noise condition. Performance accuracy was also degraded. Significantly more error responses occurred at higher noise levels; a direct or positive relation was found between error responses and noise level experienced by the subjects.

  11. Low-Resistant Band-Passing Noise and Its Dynamical Effects

    NASA Astrophysics Data System (ADS)

    Bai, Zhan-Wu

    2007-07-01

    We propose an n-order noise, which is realized by driving an n-order linear differential equation with a Gaussian white noise. The time-derivative noise is a low-resistant band-passing noise. If the derivative noise is regarded as a thermal one, the system has a vanishing effective friction and it should induce ballistic diffusion of a free particle at long times. The simulation method for the generalized Langevin equation driven by the n-order noise is discussed systematically. The features of three-order derivative noises are presented when they are applied to a ratchet system.

  12. Anthropogenic aerosol effects on East Asian winter monsoon: The role of black carbon-induced Tibetan Plateau warming

    NASA Astrophysics Data System (ADS)

    Jiang, Yiquan; Yang, Xiu-Qun; Liu, Xiaohong; Yang, Dejian; Sun, Xuguang; Wang, Minghuai; Ding, Aijun; Wang, Tijian; Fu, Congbin

    2017-06-01

    This study investigates anthropogenic aerosol effects on East Asian winter monsoon (EAWM) with Community Atmospheric Model version 5. In winter, the anthropogenic aerosol optical depth is the largest over southern East Asia and adjacent oceans. The associated EAWM change, however, is the most significant in northern East Asia, which is characterized by a significant surface cooling in northern East Asia and an acceleration of the jet stream around 40°N, indicating an intensification of the EAWM northern mode. Such an intensification is attributed to anthropogenic black carbon (BC)-induced Tibetan Plateau (TP) warming. The BC is mostly transported from northern South Asia by wintertime westerly and southwesterly and then deposited on snow, giving rise to a reduction of surface albedo and an increase of surface air temperature via the snow-albedo feedback. The TP warming increases meridional temperature gradient and lower tropospheric baroclinicity over northern East Asia, leading to the jet stream acceleration around 40°N and the westward shift of East Asian major trough via the transient eddy-mean flow feedback. Such upper tropospheric pattern favors more cold air outbreak, leading to a large surface cooling in northern East Asia. In southern East Asia, the effect of nonabsorbing aerosols is dominant. The solar flux at surface is significantly reduced directly by scattering of nonabsorbing aerosols and indirectly by intensification of short wave cloud forcing. Accordingly, the surface air temperature in southern East Asia is reduced. The precipitation is also significantly reduced in South China and Indo-China Peninsula, where the aerosol indirect effect is the largest.

  13. The Role of Negative Statements on the Subjective Effects of Traffic Noise

    NASA Astrophysics Data System (ADS)

    Nieves Vera, M.; Vila, J.; Godoy, J. F.

    1995-12-01

    This study assesses subjective effects of traffic noise and the mediator role that negative statements about the noise and about oneself play. Eighty-four students underwent two 15-minute presentations of high intensity traffic noise, with and without negative statements. The potential effect of the negative statements was enhanced by the use of instructions concerning the expectation of negative noise effects and the credibility of the statements in half the subjects. Level of anxiety, subjective noise aversion and time estimation of the noise were taken. The State Anxiety Inventory and the Profile of Mood States Questionnaire were used as pre- and post-tests. Noise increased anxiety levels, these levels being higher during the Statements condition than during the Noise alone condition. Instructions further increased the effects of these negative statements. Subjects did not adapt to noise. Scores in the questionnaires were significantly higher in the post-test than in the pre-test. Implications of these results are discussed.

  14. Three-dimensional effects on pure tone fan noise due to inflow distortion. [rotor blade noise prediction

    NASA Technical Reports Server (NTRS)

    Kobayashi, H.

    1978-01-01

    Two dimensional, quasi three dimensional and three dimensional theories for the prediction of pure tone fan noise due to the interaction of inflow distortion with a subsonic annular blade row were studied with the aid of an unsteady three dimensional lifting surface theory. The effects of compact and noncompact source distributions on pure tone fan noise in an annular cascade were investigated. Numerical results show that the strip theory and quasi three-dimensional theory are reasonably adequate for fan noise prediction. The quasi three-dimensional method is more accurate for acoustic power and model structure prediction with an acoustic power estimation error of about plus or minus 2db.

  15. Noise pollution resources compendium

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A compendium is presented of documents on noise. The articles presented are categorized in the following sections: noise sources, noise detection and measurement, noise abatement and control, physical effects of noise, psychological and physiological effects of noise, noise regulations and standards, patents and contracts, and noise research.

  16. Geomorphology of anthropogenic landscapes

    NASA Astrophysics Data System (ADS)

    Sofia, Giulia; Tarolli, Paolo

    2015-04-01

    The construction of urban areas and the development of road networks leave a significant signature on the Earth surface, providing a geomorphological evidence to support the idea that humans are nowadays a geomorphic agent having deep effects on the morphological organization of the landscape. The reconstruction or identification of anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the Anthropocene. Following this research line, the present study tests the effectiveness of a recently published topographic index, the Slope Local Length of Autocorrelation (SLLAC, Sofia et al. 2014) to portrait anthropogenic geomorphology, focusing in particular on road network density, and urban complexity (UCI). At first, the research considers the increasing of anthropic structures and the resulting changes in the SLLAC and in two derived parameters (mean SLLAC per km2 and SLLAC roughness, or Surface Peak Curvature -Spc). As a second step, considering the SLLAC derived indices, the anthropogenic geomorphology is automatically depicted using a k-means clustering algorithm. In general, the increasing of road network density or of the UCI is positively correlated to the mean SLLAC per km2, while the Spc is negatively correlated to the increasing of the anthropic structures. Areas presenting different road network organization are effectively captured considering multiple combinations of the defined parameters. Landscapes with small scattered towns, and a network with long roads in a dendritic shape (with hierarchical branching) are characterized simultaneously by high mean SLLAC and low Spc. Large and complex urban areas served by rectilinear networks with numerous short straight lines and right angles, have either a maximized mean SLLAC or a minimized Spc or both. In all cases, the anthropogenic landscape identified by the procedure is comparable to the ones identified manually from orthophoto, with the

  17. The effect of numbers of noise events on people's reactions to noise - An analysis of existing survey data

    NASA Technical Reports Server (NTRS)

    Fields, J. M.

    1984-01-01

    Even though there are surveys in which annoyance decreases as the number of events increases above about 150 a day, the available evidence is not considered strong enough to reject the conventional assumption that reactions are related to the logarithm of the number of events. The data do not make it possible to reject the conventional assumption that the effects of the number of events and the peak noise level are additive. It is found that even when equivalent questionnaire items and definitions of noise events could be used, differences between the surveys' estimates of the effect of the number of events remained large. Three explanations are suggested for inconsistent estimates. The first has to do with errors in specifying the values of noise parameters, the second with the effects of unmeasured acoustical and area characteristics that are correlated with noise level or number, and the third with large sampling errors deriving from community differences in response to noise. It is concluded that significant advances in the knowledge about the effects of the number of noise events can be made only if surveys include large numbers of study areas.

  18. Effects of climate change and anthropogenic modification on a disturbance-dependent species in a large riverine system

    USGS Publications Warehouse

    Zeigler, Sara; Catlin, Daniel H.; Bomberger Brown, M.; Fraser, J.D.; Dinan, Lauren R.; Hunt, Kelsi L.; Jorgensen, Joel G.; Karpanty, Sarah M.

    2017-01-01

    Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the

  19. Effects of activity interference on annoyance due to aircraft noise

    NASA Technical Reports Server (NTRS)

    Willshire, K. F.; Powell, C. A.

    1981-01-01

    The effects of aircraft flyover noise on annoyance were compared for face to face conversation, reverie, and television viewing. Eighteen 5 minute sessions, each composed of three flyovers, were presented on each of 2 days to subjects in a simulated living room. Twelve pairs of females and 12 pairs of males were tested, once before and once after work. Flyovers varied in peak noise level from 53 to 83 dB, A weighted. On each day, subjects engaged in 18 sessions, six of conversation, six of television viewing, and six of reverie. The subjects completed subjective ratings of annoyance and acceptability following every session. Annoyance and unacceptability rating scores were significantly higher for the activity of television viewing compared to conversation or reverie. There was no difference between judgments during the latter two activities. No differences were found in the judgments when compared on the basis of "fatigue" (before/after work) or sex of the subject.

  20. Unconventional Impacts from Unconventional Hydropower Devices: The Environmental Effects of Noise, Electromagnetic Fields, and other Stressors

    NASA Astrophysics Data System (ADS)

    Bevelhimer, M.; Cada, G. F.

    2011-12-01

    Conventional dam-based hydropower production produces a variety of environmental stressors that have been debated and confronted for decades. In-current hydrokinetic devices present some of the same or analogous stressors (e.g., changes in sediment transport and deposition, interference with animal movements and migrations, and strike by rotor blades) and some potentially new stressors (e.g., noise during operation, emission of electromagnetic fields [EMF], and toxicity of paints, lubricants, and antifouling coatings). The types of hydrokinetic devices being proposed and tested are varied, as are the locations where they could be deployed, i.e., coastal, estuarine, and big rivers. Differences in hydrology, device type, and the affected aquatic community (marine, estuarine, and riverine) will likely result in a different suite of environmental concerns for each project. Studies are underway at the U.S. Department of Energy's national laboratories to characterize the level of exposure to these stressors and to measure environmental response where possible. In this presentation we present results of studies on EMF, noise, and benthic habitat alteration relevant to hydrokinetic device operation in large rivers. In laboratory studies we tested the behavioral response of a variety of fish and invertebrate organisms to exposure to DC and AC EMF. Our findings suggest that lake sturgeon may be susceptible to EMF like that emitted from underwater cables, but most other species tested are not. Based on recordings of various underwater noise sources, we will show how the spectral density of noises created by hydrokinetic devices compares to that from other anthropogenic sources and natural sources. We will also report the results of hydroacoustic surveys that show how sediments are redistributed behind pilings like those that could be used for mounting hydrokinetic devices. The potential effects of these stressors will be discussed in the context of possible fish population

  1. Anthropogenic Space Weather

    NASA Astrophysics Data System (ADS)

    Gombosi, T. I.; Baker, D. N.; Balogh, A.; Erickson, P. J.; Huba, J. D.; Lanzerotti, L. J.

    2017-04-01

    Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release experiments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.

  2. Effects of Attack and Uncontrollable Noise on Aggression

    ERIC Educational Resources Information Center

    Geen, Russell G.

    1978-01-01

    The past decade has been marked by mounting public concern over noise as a source of environmental pollution. Simultaneously, research has shown that noise is also a potent cause of physiological stress. This research relates noise to aggression concluding that noise facilitates aggression in subjects who have been instigated to aggress to the…

  3. Interactive effects of natural and anthropogenic factors on growth and physiology of southern red spruce

    SciTech Connect

    McLaughlin, S.B.; Andersen, C.P.; Hanson, P.J.; Norby, R.J.; Edwards, N.T.; Tardiff, R.R.

    1987-01-01

    Field and laboratory studies are underway to characterize physiologial changes associated with the decline of red spruce (Picea rubens Sarg.) at high elevations in the Great Smocky Mountains National Park. Two research plots have been established on Clingman's Dome at 1720 m and 1935 m elevations to document the magnitude of growth changes at sites experiencing varying degrees of growth decline and to explore the physiological basis of observed differences. The objective is to evaluate likely mechanisms of action and identify natural and anthropogenic factors influencing the observed growth patterns. Field measurements include historical and current radial growth of mature trees and saplings, and seasonal patterns of carbon assimilation, carbon allocation, and water relations of saplings. Laboratory experiments include dose response exposures with H/sub 2/O/sub 2/, toxicity screening studies with Al, Mn, and Ca, and characterization of the foliar uptake and metabolism of nitrogen oxides. 9 refs., 2 figs., 6 tabs.

  4. Is there a robust effect of anthropogenic aerosols on the Southern Annular Mode?

    NASA Astrophysics Data System (ADS)

    Steptoe, H.; Wilcox, L. J.; Highwood, E. J.

    2016-09-01

    Historical anthropogenic aerosol (AA) changes are found to have caused a statistically significant negative Southern Annular Mode (SAM) trend (associated with an equatorward jet shift) in 14 out of 35 individual ensemble members from the fifth Coupled Model Intercomparison Project (CMIP5) since 1860. However, this response is not robust. The significance of the SAM response to aerosol is model dependent and not simply related to aerosol forcing. Multiple sources of uncertainty result in a nonrobust response that means that the model mechanism connecting remote Northern Hemisphere AA forcing remains unclear. Analysis of single forcing experiments suggests that assuming the climate response to individual model forcings to be linearly additive cannot be made without proper assessment. Our results suggest that AAs may have had a historical influence on the SAM, but its influence may be overstated by assuming linearity.

  5. Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

    2015-08-01

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

  6. Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Unger, N.; Hodzic, A.; Emmons, L.; Knote, C.; Tilmes, S.; Lamarque, J.-F.; Yu, P.

    2015-12-01

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for the no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9-5.6, 6.4-12.0 and 0.9-2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

  7. Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

    DOE PAGES

    Zheng, Y.; Unger, N.; Hodzic, A.; ...

    2015-12-08

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for themore » no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9–5.6, 6.4–12.0 and 0.9–2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

  8. Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

    DOE PAGES

    Zheng, Y.; Unger, N.; Hodzic, A.; ...

    2015-08-28

    Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution ofmore » US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.« less

  9. Noise monitoring and adverse health effects in residents in different functional areas of Luzhou, China.

    PubMed

    Han, Zhi-Xia; Lei, Zhang-Heng; Zhang, Chun-Lian; Xiong, Wei; Gan, Zhong-Lin; Hu, Ping; Zhang, Qing-Bi

    2015-03-01

    The purpose of the study was to investigate the noise pollution situation and the resulting adverse effect on residents' health in Luzhou, China, to provide data for noise pollution prevention policies and interventions. Four different functional areas (commercial, construction, residential, and transportation hub areas) were chosen to monitor noise level for 3 months. The survey was performed by questionnaire on the spot on randomly selected individuals; it collected data on the impact of noise on residents' health (quality of sleep, high blood pressure, subjective feeling of nervous system damage, and attention) as well as the knowledge of noise-induced health damage, the degree of adaptation to noise, and their solutions. The noise levels of residential, commercial, transportation, and construction areas exceeded the national standards (P < .001). Sleep quality, prevalence of hypertension, and attention in transportation hub areas were significantly different from those in the other 3 areas (P < .05); only 24.46% of people knew the health hazards associated with noise; 64.57% of residents have adapted to the current noise environment. Most of them have to close the doors and windows to reduce noise. The noise pollution situation in Luzhou, China, is serious, especially the traffic noise pollution. Residents pay less attention to it and adopt single measures to reduce the noise. We should work toward the prevention and control of traffic noise and improve the residents' awareness to reduce the adverse health effects of noise.

  10. Climatic Effects of 1950-2050 Changes in US Anthropogenic Aerosols. Part 1; Aerosol Trends and Radiative Forcing

    NASA Technical Reports Server (NTRS)

    Leibensperger, E. M.; Mickley, L. J.; Jacob, D. J.; Chen, W.-T.; Seinfeld, J. H.; Nenes, A.; Adams, P. J.; Streets, D. G.; Kumar, N.; Rind, D.

    2012-01-01

    We calculate decadal aerosol direct and indirect (warm cloud) radiative forcings from US anthropogenic sources over the 1950-2050 period. Past and future aerosol distributions are constructed using GEOS-Chem and historical emission inventories and future projections from the IPCC A1B scenario. Aerosol simulations are evaluated with observed spatial distributions and 1980-2010 trends of aerosol concentrations and wet deposition in the contiguous US. Direct and indirect radiative forcing is calculated using the GISS general circulation model and monthly mean aerosol distributions from GEOS-Chem. The radiative forcing from US anthropogenic aerosols is strongly localized over the eastern US. We find that its magnitude peaked in 1970-1990, with values over the eastern US (east of 100 deg W) of -2.0Wm(exp-2 for direct forcing including contributions from sulfate (-2.0Wm-2), nitrate (-0.2Wm(exp-2), organic carbon (-0.2Wm(exp-2), and black carbon (+0.4Wm(exp-2). The uncertainties in radiative forcing due to aerosol radiative properties are estimated to be about 50 %. The aerosol indirect effect is estimated to be of comparable magnitude to the direct forcing. We find that the magnitude of the forcing declined sharply from 1990 to 2010 (by 0.8Wm(exp-2) direct and 1.0Wm(exp-2 indirect), mainly reflecting decreases in SO2 emissions, and project that it will continue declining post-2010 but at a much slower rate since US SO2 emissions have already declined by almost 60% from their peak. This suggests that much of the warming effect of reducing US anthropogenic aerosol sources has already been realized. The small positive radiative forcing from US BC emissions (+0.3Wm(exp-2 over the eastern US in 2010; 5% of the global forcing from anthropogenic BC emissions worldwide) suggests that a US emission control strategy focused on BC would have only limited climate benefit.

  11. Alien plant invasion in mixed-grass prairie: effects of vegetation type, stochiasticity, and anthropogenic disturbance in two park units

    USGS Publications Warehouse

    Larson, Diane L.; Anderson, Patrick J.; Newton, Wesley E.

    2001-01-01

    The ability of alien plant species to invade a region depends not only on attributes of the plant, but on characteristics of the habitat being invaded. Here, we examine characteristics that may influence the success of alien plant invasion in mixed-grass prairie at Theodore Roosevelt National Park, in western North Dakota, USA. The park consists of two geographically separate units with similar vegetation types and management history, which allowed us to examine the effects of native vegetation type, anthropogenic disturbance, and the separate park units on the invasion of native plant communities by alien plant species common to counties surrounding both park units. If matters of chance related to availability of propagules and transient establishment opportunities determine the success of invasion, park unit and anthropogenic disturbance should better explain the variation in alien plant frequency. If invasibility is more strongly related to biotic or physical characteristics of the native plant communities, models of alien plant occurrence should include vegetation type as an explanatory variable. We examined >1300 transects across all vegetation types in both units of the park. Akaike's Information Criterion (AIC) indicated that the fully parameterized model, including the interaction among vegetation type, disturbance, and park unit, best described the distribution of both total number of alien plants per transect and frequency of alien plants on transects where they occurred. Although all vegetation types were invaded by alien plants, mesic communities had both greater numbers and higher frequencies of alien plants than did drier communities. A strong element of stochasticity, reflected in differences in frequencies of individual species between the two park units, suggests that prediction of risk of invasion will always involve uncertainty. In addition, despite well-documented associations between anthropogenic disturbance and alien plant invasion, five of

  12. Effects of anthropogenic emissions on the molecular composition of urban organic aerosols: An ultrahigh resolution mass spectrometry study

    NASA Astrophysics Data System (ADS)

    Kourtchev, I.; O'Connor, I. P.; Giorio, C.; Fuller, S. J.; Kristensen, K.; Maenhaut, W.; Wenger, J. C.; Sodeau, J. R.; Glasius, M.; Kalberer, M.

    2014-06-01

    Identification of the organic composition of atmospheric aerosols is necessary to develop effective air pollution mitigation strategies. However, the majority of the organic aerosol mass is poorly characterized and its detailed analysis is a major analytical challenge. In this study, we applied state-of-the-art direct infusion nano-electrospray (nanoESI) ultrahigh resolution mass spectrometry (UHRMS) and liquid chromatography ESI Quadrupole Time-of-Flight (Q-TOF) MS for the analysis of the organic fraction of fine particulate matter (PM2.5) collected at an urban location in Cork, Ireland. Comprehensive mass spectral data evaluation methods (e.g., Kendrick Mass Defect and Van Krevelen) were used to identify compound classes and mass distributions of the detected species. Up to 850 elemental formulae were identified in negative mode nanoESI-UHR-MS. Nitrogen and/or sulphur containing organic species contributed up to 40% of the total identified formulae and exhibited strong diurnal variations suggesting the importance of night-time NO3 chemistry at the site. The presence of a large number of oxidised aromatic and nitroaromatic compounds in the samples indicated a strong anthropogenic influence, i.e., from traffic emissions and domestic solid fuel (DSF) burning. Most of the identified biogenic secondary organic aerosol (SOA) compounds are later-generation nitrogen- and sulphur-containing products, indicating that SOA composition is strongly affected by anthropogenic species such as NOx and SO2. Unsaturated and saturated C12-C20 fatty acids were found to be the most abundant homologs with a composition reflecting a primary marine origin. The results of this work demonstrate that the studied site is a very complex environment affected by a variety of anthropogenic activities and natural sources.

  13. Effects of noise on the phase dynamics of nonlinear oscillators

    NASA Astrophysics Data System (ADS)

    Daffertshofer, A.

    1998-07-01

    Various properties of human rhythmic movements have been successfully modeled using nonlinear oscillators. However, despite some extensions towards stochastical differential equations, these models do not comprise different statistical features that can be explained by nondynamical statistics. For instance, one observes certain lag one serial correlation functions for consecutive periods during periodic motion. This work aims at an extension of dynamical descriptions in terms of stochastically forced nonlinear oscillators such as ξ¨+ω20ξ=n(ξ,ξ˙)+q(ξ,ξ˙)Ψ(t), where the nonlinear function n(ξ,ξ˙) generates a limit cycle and Ψ(t) denotes colored noise that is multiplied via q(ξ,ξ˙). Nonlinear self-excited systems have been frequently investigated, particularly emphasizing stability properties and amplitude evolution. Thus, one can focus on the effects of noise on the frequency or phase dynamics that can be analyzed by use of time-dependent Fokker-Planck equations. It can be shown that noise multiplied via polynoms of arbitrary finite order cannot generate the desired period correlation but predominantly results in phase diffusion. The system is extended in terms of forced oscillators in order to find a minimal model producing the required error correction.

  14. Effects of Hyperlipidemia on Noise Induced Hearing Loss (NIHL).

    PubMed

    Doosti, Afsaneh; Lotfi, Yones; Bakhshi, Enayatollah

    2016-06-01

    Likelihood of developing noise induced hearing loss (NIHL) is affected by some factors such as genes, nutrition and healthy hearing habits. We investigated this study to determine the effect of hyperlipidemia on NIHL. In a case-control study, 144 workers who exposed to continuous noise more than 85 dBA (88-89 dBA) from a textile factory in Tehran were examined. Serum Blood test results as index for dyslipidemi, were collected and audiometry tests were carried out to analyze the association of hyperlipidemian and NIHL. The mean ±SD of Cholesterol level for NIHL and control were 188.19 (28.46) and 159.00 (26.66) mg/dL respectively. Also the mean ±SD of Triglyceride level for NIHL and control were 203.75 (53.92) and 105.00 (30.50) mg/dL consecutively. After adjusting odds ratio (OR) for NIHL, only hypertriglyceridemia had association with NIHL. (aOR = 1.07; 95 % CI 1.04-1.10), and there wasn't any relation between hypercholestomia and NIHL (aOR = 1.02; 95 % CI 0.99-1.05). Workers with hypertriglyceridemia are at increased risk for NIHL. In factories with elevated noise levels, besides hearing conservation programs, attention to blood serum level of workers and healthy diet are proposed to help in preserving hearing threshold.

  15. Effects of Geometric Details on Slat Noise Generation and Propagation

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Lockhard, David P.

    2006-01-01

    The relevance of geometric details to the generation and propagation of noise from leading-edge slats is considered. Typically, such details are omitted in computational simulations and model-scale experiments thereby creating ambiguities in comparisons with acoustic results from flight tests. The current study uses two-dimensional, computational simulations in conjunction with a Ffowcs Williams-Hawkings (FW-H) solver to investigate the effects of previously neglected slat "bulb" and "blade" seals on the local flow field and the associated acoustic radiation. The computations clearly show that the presence of the "blade" seal at the cusp significantly changes the slat cove flow dynamics, reduces the amplitudes of the radiated sound, and to a lesser extent, alters the directivity beneath the airfoil. Furthermore, it is demonstrated that a modest extension of the baseline "blade" seal further enhances the suppression of slat noise. As a side issue, the utility and equivalence of FW-H methodology for calculating far-field noise as opposed to a more direct approach is examined and demonstrated.

  16. Effects of Geometric Details on Slat Noise Generation and Propagation

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Lockard, David P.

    2009-01-01

    The relevance of geometric details to the generation and propagation of noise from leading-edge slats is considered. Typically, such details are omitted in computational simulations and model-scale experiments thereby creating ambiguities in comparisons with acoustic results from flight tests. The current study uses two-dimensional, computational simulations in conjunction with a Ffowcs Williams-Hawkings (FW-H) solver to investigate the effects of previously neglected slat "bulb" and "blade" seals on the local flow field and the associated acoustic radiation. The computations show that the presence of the "blade" seal at the cusp in the simulated geometry significantly changes the slat cove flow dynamics, reduces the amplitudes of the radiated sound, and to a lesser extent, alters the directivity beneath the airfoil. Furthermore, the computations suggest that a modest extension of the baseline "blade" seal further enhances the suppression of slat noise. As a side issue, the utility and equivalence of FW-H methodology for calculating far-field noise as opposed to a more direct approach is examined and demonstrated.

  17. Lossless Astronomical Image Compression and the Effects of Random Noise

    NASA Technical Reports Server (NTRS)

    Pence, William

    2009-01-01

    In this paper we compare a variety of modern image compression methods on a large sample of astronomical images. We begin by demonstrating from first principles how the amount of noise in the image pixel values sets a theoretical upper limit on the lossless compression ratio of the image. We derive simple procedures for measuring the amount of noise in an image and for quantitatively predicting how much compression will be possible. We then compare the traditional technique of using the GZIP utility to externally compress the image, with a newer technique of dividing the image into tiles, and then compressing and storing each tile in a FITS binary table structure. This tiled-image compression technique offers a choice of other compression algorithms besides GZIP, some of which are much better suited to compressing astronomical images. Our tests on a large sample of images show that the Rice algorithm provides the best combination of speed and compression efficiency. In particular, Rice typically produces 1.5 times greater compression and provides much faster compression speed than GZIP. Floating point images generally contain too much noise to be effectively compressed with any lossless algorithm. We have developed a compression technique which discards some of the useless noise bits by quantizing the pixel values as scaled integers. The integer images can then be compressed by a factor of 4 or more. Our image compression and uncompression utilities (called fpack and funpack) that were used in this study are publicly available from the HEASARC web site.Users may run these stand-alone programs to compress and uncompress their own images.

  18. Airport noise

    NASA Technical Reports Server (NTRS)

    Pendley, R. E.

    1982-01-01

    The problem of airport noise at several airports and air bases is detailed. Community reactions to the noise, steps taken to reduce jet engine noise, and the effect of airport use restrictions and curfews on air transportation are discussed. The adverse effect of changes in allowable operational noise on airport safety and altenative means for reducing noise pollution are considered. Community-airport relations and public relations are discussed.

  19. Effects of anthropogenic activities on the heavy metal levels in the clams and sediments in a tropical river.

    PubMed

    Wong, Koe Wei; Yap, Chee Kong; Nulit, Rosimah; Hamzah, Mohd Suhaimi; Chen, Soo Kien; Cheng, Wan Hee; Karami, Ali; Al-Shami, Salman Abdo

    2017-01-01

    The present study aimed to assess the effects of anthropogenic activities on the heavy metal levels in the Langat River by transplantation of Corbicula javanica. In addition, potential ecological risk indexes (PERI) of heavy metals in the surface sediments of the river were also investigated. The correlation analysis revealed that eight metals (As, Co, Cr, Fe, Mn, Ni, Pb and Zn) in total soft tissue (TST) while five metals (As, Cd, Cr, Fe and Mn) in shell have positively and significantly correlation with respective metal concentration in sediment, indicating the clams is a good biomonitor of the metal levels. Based on clustering patterns, the discharge of dam impoundment, agricultural activities and urban domestic waste were identified as three major contributors of the metals in Pangsun, Semenyih and Dusun Tua, and Kajang, respectively. Various geochemical indexes for a single metal pollutant (geoaccumulation index (I geo), enrichment factors (EF), contamination factor (C f) and ecological risk (Er)) all agreed that Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn are not likely to cause adverse effect to the river ecosystem, but As and Pb could pose a potential ecological risk to the river ecosystem. All indexes (degree of contamination (C d), combined pollution index (CPI) and PERI) showed that overall metal concentrations in the tropical river are still within safe limit. River metal pollution was investigated. Anthropogenic activities were contributors of the metal pollution. Geochemical indexes showed that metals are within the safe limit.

  20. Effects of background noise on audiometric thresholds during positron emission tomography: passive and active noise-reduction.

    PubMed

    Kim, K; Burkard, R F; Lockwood, A H; Salvi, R J

    2000-01-01

    Position emission tomography (PET) is used to assess the functional activity of the human auditory brain; however, the activity detected by PET could be affected by ambient acoustic noise from the PET equipment. To evaluate these effects, we compared behavioural thresholds in the PET camera with those measured in an audiometric sound booth. Thresholds were measured with: (i) ER2 earphones, (ii) ER2 earphones + Cabot earmuffs, (iii) ER2 earphones + Bose Series II Aviation Headset with active noise-reduction off, and (iv) ER2 earphones + Bose Series II Aviation Headset with active noise-reduction on. Overall ambient noise level in the camera was 73 dB SPL and the maximum octave-band SPL was 68 dB SPL at 250 Hz. Threshold elevations in the PET camera were greatest with ER2 (17 dB, 125 Hz) earphones and lowest with ER2 earphones + Bose Series II Aviation Headset (8 dB at 250 Hz) with active noise-reduction. Thus, PET scanner noise had little or no effect on threshold when stimuli were presented through ER2 earphones covered with an activated Bose Series II Aviation Headset.

  1. MACv2-SP: a parameterization of anthropogenic aerosol optical properties and an associated Twomey effect for use in CMIP6

    NASA Astrophysics Data System (ADS)

    Stevens, Bjorn; Fiedler, Stephanie; Kinne, Stefan; Peters, Karsten; Rast, Sebastian; Müsse, Jobst; Smith, Steven J.; Mauritsen, Thorsten

    2017-02-01

    A simple plume implementation of the second version (v2) of the Max Planck Institute Aerosol Climatology, MACv2-SP, is described. MACv2-SP provides a prescription of anthropogenic aerosol optical properties and an associated Twomey effect. It was created to provide a harmonized description of post-1850 anthropogenic aerosol radiative forcing for climate modeling studies. MACv2-SP has been designed to be easy to implement, change and use, and thereby enable studies exploring the climatic effects of different patterns of aerosol radiative forcing, including a Twomey effect. MACv2-SP is formulated in terms of nine spatial plumes associated with different major anthropogenic source regions. The shape of the plumes is fit to the Max Planck Institute Aerosol Climatology, version 2, whose present-day (2005) distribution is anchored by surface-based observations. Two types of plumes are considered: one predominantly associated with biomass burning, the other with industrial emissions. These differ in the prescription of their annual cycle and in their optical properties, thereby implicitly accounting for different contributions of absorbing aerosol to the different plumes. A Twomey effect for each plume is prescribed as a change in the host model's background cloud-droplet population density using relationships derived from satellite data. Year-to-year variations in the amplitude of the plumes over the historical period (1850-2016) are derived by scaling the plumes with associated national emission sources of SO2 and NH3. Experiments using MACv2-SP are performed with the Max Planck Institute Earth System Model. The globally and annually averaged instantaneous and effective aerosol radiative forcings are estimated to be -0.6 and -0.5 W m-2, respectively. Forcing from aerosol-cloud interactions (the Twomey effect) offsets the reduction of clear-sky forcing by clouds, so that the net effect of clouds on the aerosol forcing is small; hence, the clear-sky forcing, which is more

  2. Effect of noise on Frequency-Resolved Optical Gating measurements of ultrashort pulses

    SciTech Connect

    Fittinghoff, D.N.; DeLong, K.W.; Ladera, C.L.; Trebino, R.

    1995-02-01

    We study the effects of noise in Frequency-Resolved Optical Gating measurements of ultrashort pulses. We quantify the measurement accuracy in the presence of additive, muliplicative, and quantization noise, and discuss filtering and pre-processing of the data.

  3. Effects on sleep of noise from two proposed STOL aircraft

    NASA Technical Reports Server (NTRS)

    Lukas, J. S.; Peeler, D. J.; Davis, J. E.

    1975-01-01

    Responses, both overt behavior and those measured by electroencephalograph, to noise by eight male subjects were studied for sixteen consecutive nights. Test stimuli were: (1) The simulated sideline noise of a short takeoff and landing aircraft with blown flaps; (2) the simulated sideline noise of a STOL aircraft of turbofan design; (3) the simulated takeoff noise of the blown flap STOL aircraft; and (4) a four second burst of simulated pink noise. Responses to each noise were tested at three noise intensities selected to represent levels expected indoors from operational aircraft. The results indicate that the blown flap STOL aircraft noise resulted in 8 to 10 percent fewer sleep disturbance responses than did the turbofan STOL aircraft when noises of comparable intensities from similar maneuvers were used.

  4. Rough analysis of installation effects on turboprop noise

    NASA Technical Reports Server (NTRS)

    Durbin, P. A.; Groeneweg, J. F.

    1982-01-01

    A rough analysis of noise from a propeller operated at angle of attack, and in the nonuniform flow due to a line vortex approximating a wing flow field suggests installation can significantly affect turboprop noise levels. On one side of the propeller, where the blades approach the horizontal plane from above, decreases of noise occur; while on the other side noise increases. The noise reduction is due to negative interference of steady and unsteady sources. An angle of attack, or distance between propeller and vortex, exists for which noise is a minimum.

  5. Effects of ship noise on the detectability of communication signals in the Lusitanian toadfish.

    PubMed

    Vasconcelos, Raquel O; Amorim, M Clara P; Ladich, Friedrich

    2007-06-01

    Underwater noise pollution is an increasing environmental problem which might affect communication, behaviour, fitness and consequently species' survival. The most common anthropogenic noises in aquatic habitats derive from shipping. In the present study we investigated the implications of noise pollution from a ship on the sound detectability, namely of conspecific vocalizations in the Lusitanian toadfish, Halobatrachus didactylus. Ambient and ferry-boat noises were recorded in the Tagus River estuary (Portugal), as well as toadfish sounds, and their sound pressure levels determined. Hearing sensitivities were measured under quiet lab conditions and in the presence of these masking noises at levels encountered in the field, using the auditory evoked potentials (AEP) recording technique. The Lusitanian toadfish is a hearing generalist, with best hearing sensitivity at low frequencies between 50 and 200 Hz (below 100 dB re. 1 microPa). Under ambient noise conditions, hearing was only slightly masked at lower frequencies. In the presence of ship noise, auditory thresholds increased considerably, by up to 36 dB, at most frequencies tested. This is mainly because the main energies of ferry-boat noise were within the most sensitive hearing range of this species. Comparisons between masked audiograms and sound spectra of the toadfish's mating and agonistic vocalizations revealed that ship noise decreased the ability to detect conspecific acoustic signals. This study provides the first evidence that fishes' auditory sensitivity can be impaired by ship noise and that acoustic communication, which is essential during agonistic encounters and mate attraction, might be restricted in coastal environments altered by human activity.

  6. Long-term effects of noise reduction measures on noise annoyance and sleep disturbance: the Norwegian facade insulation study.

    PubMed

    Amundsen, Astrid H; Klæboe, Ronny; Aasvang, Gunn Marit

    2013-06-01

    The Norwegian facade insulation study includes one pre-intervention and two post-intervention surveys. The facade-insulating measures reduced indoor noise levels by 7 dB on average. Before the intervention, 43% of the respondents were highly annoyed by noise. Half a year after the intervention, the proportion of respondents who were highly annoyed by road traffic noise had been significantly reduced to 15%. The second post-intervention study (2 yr after the first post-intervention study) showed that the proportion of highly annoyed respondents had not changed since the first post-intervention study. The reduction in the respondents' self-reported sleep disturbances (due to traffic noise) also remained relatively stable from the first to the second post-intervention study. In the control group, there were no statistically significant differences in annoyance between the pre-intervention and the two post-intervention studies. Previous studies of traffic changes have reported that people "overreact" to noise changes. This study indicated that when considering a receiver measure, such as facade insulation, the effect of reducing indoor noise levels could be predicted from exposure-response curves based on previous studies. Thus no evidence of an "overreaction" was found.

  7. Towards the detection and attribution of an anthropogenic effect on climate

    SciTech Connect

    Santer, B.D.; Taylor, K.E.; Penner, J.E.; Wigley, T.M.L.; Jones, P.D.; Cubasch, U.

    1995-01-01

    It has been hypothesized recently that cooling caused by anthropogenic sulfate aerosols may be obscuring a warming signal associated with changes in greenhouse gas concentrations. Here the authors use results from model experiments in which sulfate and carbon dioxide have been varied individually and in combination in order to determine whether the simulated surface temperature change patterns are increasingly evident in observed records of temperature change. They use centered [R(t)] and uncentered [C(t)] pattern correlation statistics in order to compare observed time-evolving surface temperature change patterns with the model-predicted equilibrium signal patterns. They show that in the case of temperature signals from the ``CO{sub 2}-only`` and ``sulfate-only`` experiments, the C(t) statistic essentially reduces to a measure of observed global-mean temperature changes, and cannot be used to uniquely attribute observed climate changes to a specific causal mechanism. For the signal from the experiment with combined CO{sub 2}/sulfate aerosol forcing, C(t) provides information on pattern congruence, but trends in C(t) are difficult to interpret without decomposing the statistic into pattern similarity and global-mean change components. They therefore focus on R(t), which is a more useful statistic for discriminating between forcing mechanisms with different pattern signatures but similar rates of global mean change.

  8. Geochemical characterization of anthropogenic effects in coastal lagoons at the Northern Pacific coast of Mexico

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernández, A. C.; Mellado-Vazquez, P. G.; Bojorquez-Sanchez, S.; Páez-Osuna, F.

    2007-05-01

    Sinaloa is a coastal state located in the Gulf of California that is characterized by an economy mostly based on agroindustry, fisheries, aquaculture and tourism. It has been recognized that the coastal lagoons neighboring the most developed economic areas of Sinaloa state are showing signs of infilling and eutrophication that have been related with the dumping of untreated effluents from agriculture croplands, aquaculture facilities and human settlements. The environmental impact to the lagoons of Navachiste, Santa María, Ohuira, Ensenada del Pabellón, Chiricahueto, Ceuta y Estero de Urías has been evaluated through the assessment of time dependent changes in the 210Pb-derived sedimentation rates and the sediment concentrations of geochemical constituents such as organic matter, carbonates and nutrients (N and P). 210Pb geochronology has shown that accretion rates and nutrient fluxes in some lagoons have considerably increased due to the development of the agriculture activities in the region. For instance, in Ohuira lagoon, at the area adjacent to the culture fields of El Fuerte Valley, sediment accumulation has increased ~5 times with respect to the pre-anthropogenic conditions in less than 20 years (0.06 to 0.32 cm yr-1), while C, N and P fluxes (mg cm-2 yr-1) increased almost 10, 10 and 13 fold, respectively (4.0-37 for OC, 0.6-6.0 for N and 0.1-7.0 for P).

  9. Dynamical aspects of coupled Rossler systems: effects of noise

    NASA Astrophysics Data System (ADS)

    Pravitha, R.; Indic, P.; Nampoori, V. P. N.

    2002-02-01

    Nonlinear time series analysis is employed to study the complex behaviour exhibited by a coupled pair of Rossler systems. Dimensional analysis with emphasis on the topological correlation dimension and the Kolmogorov entropy of the system is carried out in the coupling parameter space. The regime of phase synchronization is identified and the extent of synchronization between the systems constituting the coupled system is quantified by the phase synchronization index. The effect of noise on the coupling between the systems is also investigated. An exhaustive study of the topological, dynamical and synchronization properties of the nonlinear system under consideration in its characteristic parameter space is attempted.

  10. The effect of non-linear propagation in jet noise

    NASA Technical Reports Server (NTRS)

    Gallagher, J. A.

    1982-01-01

    An experimental investigation of the nonlinear propagation effects which occur in the noise radiated from low and moderate Reynolds number supersonic jets has been performed. An array of three condenser microphones was used to measure the waveforms propagated by axisymmetric, cold model jets of Mach numbers 2.1 and 2.5. Relatively low Reynolds numbers were obtained by exhausting the jets into a low pressure anechoic test chamber. The results show that phenomena normally associated with nonlinear acoustic propagation, such as wave steepening, harmonic generation and wave merging, are measurable in the high speed model jets.

  11. Approaches to Observe Anthropogenic Aerosol-Cloud Interactions.

    PubMed

    Quaas, Johannes

    Anthropogenic aerosol particles exert an-quantitatively very uncertain-effective radiative forcing due to aerosol-cloud interactions via an immediate altering of cloud albedo on the one hand and via rapid adjustments by alteration of cloud processes and by changes in thermodynamic profiles on the other hand. Large variability in cloud cover and properties and the therefore low signal-to-noise ratio for aerosol-induced perturbations hamper the identification of effects in observations. Six approaches are discussed as a means to isolate the impact of anthropogenic aerosol on clouds from natural cloud variability to estimate or constrain the effective forcing. These are (i) intentional cloud modification, (ii) ship tracks, (iii) differences between the hemispheres, (iv) trace gases, (v) weekly cycles and (vi) trends. Ship track analysis is recommendable for detailed process understanding, and the analysis of weekly cycles and long-term trends is most promising to derive estimates or constraints on the effective radiative forcing.

  12. Supersonic jet noise - Its generation, prediction and effects on people and structures

    NASA Technical Reports Server (NTRS)

    Preisser, J. S.; Golub, R. A.; Seiner, J. M.; Powell, C. A.

    1990-01-01

    This paper presents the results of a study aimed at quantifying the effects of jet source noise reduction, increases in aircraft lift, and reduced aircraft thrust on the take-off noise associated with supersonic civil transports. Supersonic jet noise sources are first described, and their frequency and directivity dependence are defined. The study utilizes NASA's Aircraft Noise Prediction Program in a parametric study to weigh the relative benefits of several approaches to low noise. The baseline aircraft concept used in these predictions is the AST-205-1 powered by GE21/J11-B14A scaled engines. Noise assessment is presented in terms of effective perceived noise levels at the FAA's centerline and sideline measuring locations for current subsonic aircraft, and in terms of audiologically perceived sound of people and other indirect effects. The results show that significant noise benefit can be achieved through proper understanding and utilization of all available approaches.

  13. Small Vessel Contribution to Underwater Noise

    SciTech Connect

    Matzner, Shari; Maxwell, Adam R.; Myers, Joshua R.; Caviggia, Kurt A.; Elster, Jennifer L.; Foley, Michael G.; Jones, Mark E.; Ogden, George L.; Sorensen, Eric L.; Zurk, Lisa M.; Tagestad, Jerry D.; Stephan, Alex J.; Peterson, Mary E.; Bradley, Donald J.

    2010-12-10

    Understanding the types of noise generated by a small boat is important for ensuring that marine ecosystems are protected from detrimental anthropogenic noise. Here we present the results of a field test conducted to examine the effects of engine RPM, number of engines and number of propeller blades on the broadband and narrowband noise produced by a small boat. The test boat was a 23-foot aluminum-hulled boat with dual 100 hp engines. The broadband noise and narrowband peak levels were observed using two hydrophones in different locations. The broadband noise levels were affected by both the number of engines and the RPM; the narrowband peaks showed a greater increase in amplitude with an increase in RPM than the broadband noise levels.

  14. Extracirculatory effects of noise of various frequency spectra in humans--effect of pink and blue noise on gastric myoelectrical activity and gastrointestinal passage of nutrients.

    PubMed

    Kasicka-Jonderko, Anna; Jonderko, Krzysztof; Dolinski, Kamil; Dolinski, Miroslaw; Kaminska, Magdalena; Szymszal, Malgorzata; Dzielicki, Marek; Blonska-Fajfrowska, Barbara

    2007-02-01

    Recent investigations in humans point out to a disturbing effect of auditory stimuli on the functional integrity of the brain-gut axis. The study was devoted to a systematic comparative evaluation of the effect of noises of different frequency spectra on the postprandial electrical and transport functions of the digestive tract in humans. Twenty six healthy subjects attended a cross-over study, which aimed at comparison of the effect of pink contrasted to blue noise within a given category (band or tonal) and a meal stimulus type (semi-liquid or solid test meal). A panel of noninvasive measurement methods was applied: heart rate variability (HRV) analysis, surface electrogastrography, (13)CO(2) breath tests for gastric emptying (GE), lactulose hydrogen breath test for orocecal transit time (OCTT). The blue tonal noise was rated the most annoying one, whereas solely the pink noises exerted discernible cardiovascular effects. No one of the four noises was capable of overriding the meal-induced preponderance of the sympathetic tone. The postprandial gastric myoelectrical activity and the GE of either the semiliquid or the solid test meal appeared to be ;resistant' to the noise exposure, irrespective of the noise type. Similar was the finding in the case of the OCTT, with the exception of a statistically significant retardation of the OCTT with the blue band noise. Ingestion of mixed caloric meals seems to elicit a protective influence against noise-elicited derangements of the functional integrity of the digestive tract proven formerly to occur during the fasting period.

  15. Teaching Doppler Effect with a passing noise source

    NASA Astrophysics Data System (ADS)

    Costa, Ivan F.; Mocellin, Alexandra

    2010-07-01

    The noise pitch variation of a passing noise source allows a low cost experimental approach to calculate speed and, for the first time, distance. We adjusted the recorded noise pitch variation to the Doppler shift equation for sound. We did this by taking into account the frequency delay due to the sound source displacement and performing a Fast Fourier Transform (FFT) of the noise signal using free software. This experimental method was successfully applied to aircraft and automobiles.

  16. Weekly cycles of global fires—Associations with religion, wealth and culture, and insights into anthropogenic influences on global climate

    NASA Astrophysics Data System (ADS)

    Earl, Nick; Simmonds, Ian; Tapper, Nigel

    2015-11-01

    One approach to quantifying anthropogenic influences on the environment and the consequences of those is to examine weekly cycles (WCs). No long-term natural process occurs on a WC so any such signal can be considered anthropogenic. There is much ongoing scientific debate as to whether regional-scale WCs exist above the statistical noise level, with most significant studies claiming that anthropogenic aerosols and their interaction with solar radiation and clouds (direct/indirect effect) is the controlling factor. A major source of anthropogenic aerosol, underrepresented in the literature, is active fire (AF) from anthropogenic burning for land clearance/management. WCs in AF have not been analyzed heretofore, and these can provide a mechanism for observed regional-scale WCs in several meteorological variables. We show that WCs in AFs are highly pronounced for many parts of the world, strongly influenced by the working week and particularly the day(s) of rest, associated with religious practices.

  17. Effects of hydrogeological and anthropogenic factors on the distribution of CVOCs in eogenetic karst aquifers

    NASA Astrophysics Data System (ADS)

    Torres Torres, N. I.; Padilla, I. Y.; Rivera, V. L.

    2016-12-01

    Eogenetic kart aquifers are characterized by well-developed conduit networks within a rock matrix having significant primary porosity and permeability. These aquifers are highly productive and serve as important source of water for multiple uses. As a consequence, eogenetic karst regions are attractive for industrial, urban, and agricultural development that can serve as contaminations sources for the aquifers. It is hypothesized that the distribution of contaminants in these aquifers are influenced by combined characteristics of source and hydrogeological features. This research assesses the spatio-temporal distribution of chlorinated volatile organic compounds (CVOCs) in the eogenetic karst aquifers of northern Puerto Rico (NPR) and studies the correlation between hydrogeological and anthropogenic variables and groundwater contamination using Geographic Information System and statistical methods. CVOCs, which are used as dry cleaning and industrial solvents, degreasers and paint or spot removers, are among the most commonly found groundwater contaminants in the world. The NPR karst aquifers have been heavily impacted by land development and groundwater contamination, particularly CVOCs, with Trichloroethylene, Tetrachloroethylene, and Carbon Tetrachloride among the most detected contaminants. The analysis shows that 62% of the samples and 78% of the sites sampled have presence of one or more CVOC, and that their concentrations vary with time. Detection and concentrations of certain CVOCs are associated with some sources of known contamination. Significant presence of CVOCs is also found near developed and agricultural land uses. The shallow aquifer shows greater presence of CVOCs (66%) than the confined aquifer (16%), with most detections occurring in areas of low and medium sinkholes coverage and medium hydraulic conductivities. Multivariate statistical analysis indicates that, indeed, the distribution of CVOCs in the karsts aquifers of NPR is influenced by a

  18. An effective, economical method of reducing environmental noise in the vivarium.

    PubMed

    Young, Maggie T; French, Alan L; Clymer, Jeffrey W

    2011-07-01

    High levels of ambient noise can have detrimental effects on laboratory animal wellbeing and may affect experimental results. In addition, excessive noise can reduce technician comfort and performance. This study was performed to determine whether inexpensive, passive acoustic noise abatement measures could meaningfully reduce noise levels. Sound level measurements for various activities were obtained in the incoming processing room for pigs before and after installing gypsum acoustic paneling, covering metal-to-metal contact points with strips of adhesive-backed rubber, and replacing hard plastic wheels on transport carts with neoprene wheels. The modifications reduced the overall average noise level by 8.1 dB. Average noise levels for each activity were all less than 85 dB after the modifications. Average noise levels can be reduced effectively and economically with passive abatement methods. Intermittent spikes in noise are more difficult to control and may require attention to the individual activity.

  19. An Effective, Economical Method of Reducing Environmental Noise in the Vivarium

    PubMed Central

    Young, Maggie T; French, Alan L; Clymer, Jeffrey W

    2011-01-01

    High levels of ambient noise can have detrimental effects on laboratory animal wellbeing and may affect experimental results. In addition, excessive noise can reduce technician comfort and performance. This study was performed to determine whether inexpensive, passive acoustic noise abatement measures could meaningfully reduce noise levels. Sound level measurements for various activities were obtained in the incoming processing room for pigs before and after installing gypsum acoustic paneling, covering metal-to-metal contact points with strips of adhesive-backed rubber, and replacing hard plastic wheels on transport carts with neoprene wheels. The modifications reduced the overall average noise level by 8.1 dB. Average noise levels for each activity were all less than 85 dB after the modifications. Average noise levels can be reduced effectively and economically with passive abatement methods. Intermittent spikes in noise are more difficult to control and may require attention to the individual activity. PMID:21838981

  20. Noise-induced transitions and resonant effects in nonlinear systems

    NASA Astrophysics Data System (ADS)

    Zaikin, Alexei

    2003-02-01

    Our every-day experience is connected with different acoustical noise or music. Usually noise plays the role of nuisance in any communication and destroys any order in a system. Similar optical effects are known: strong snowing or raining decreases quality of a vision. In contrast to these situations noisy stimuli can also play a positive constructive role, e.g. a driver can be more concentrated in a presence of quiet music. Transmission processes in neural systems are of especial interest from this point of view: excitation or information will be transmitted only in the case if a signal overcomes a threshold. Dr. Alexei Zaikin from the Potsdam University studies noise-induced phenomena in nonlinear systems from a theoretical point of view. Especially he is interested in the processes, in which noise influences the behaviour of a system twice: if the intensity of noise is over a threshold, it induces some regular structure that will be synchronized with the behaviour of neighbour elements. To obtain such a system with a threshold one needs one more noise source. Dr. Zaikin has analyzed further examples of such doubly stochastic effects and developed a concept of these new phenomena. These theoretical findings are important, because such processes can play a crucial role in neurophysics, technical communication devices and living sciences. Unsere alltägliche Erfahrung ist mit verschiedenen akustischen Einfluessen wie Lärm, aber auch Musik verbunden. Jeder weiss, wie Lärm stören kann und Kommunikation behindert oder gar unterbindet. Ähnliche optische Effekte sind bekannt: starkes Schneetreiben oder Regengüsse verschlechtern die Sicht und lassen uns Umrisse nur noch schemenhaft erkennen. Jedoch koennen ähnliche Stimuli auch sehr positive Auswirkungen haben: Autofahrer fahren bei leiser Musik konzentrierter -- die Behauptung von Schulkindern, nur bei dröhnenden Bässen die Mathehausaufgaben richtig rechnen zu können, ist allerdings nicht wissenschaftlich

  1. A field study of effects of road traffic and railway noise on polysomnographic sleep parameters.

    PubMed

    Aasvang, Gunn Marit; Øverland, Britt; Ursin, Reidun; Moum, Torbjørn

    2011-06-01

    The aim of this study was to explore and compare the effect of noise from railway and road traffic on sleep in subjects habitually exposed to nocturnal noise. Forty young and middle aged healthy subjects were studied with polysomnography (PSG) during two consecutive nights in their own bedroom. Noise measurements and recordings were conducted concurrently outside of the bedroom façade as well as inside the bedroom of each participant. Different noise exposure parameters were calculated (L(p,A,eq,night), L(p,A,Fmax,night), and L(AF5,night)) and analyzed in relation to whole-night sleep parameters. The group exposed to railway noise had significantly less Rapid eye movement, (REM) sleep than the group exposed to road traffic noise. A significant association was found between the maximum level (L(p,A,Fmax,night)) of railway noise and time spent in REM sleep. REM sleep was significantly shorter in the group exposed to at least a single railway noise event above 50 dB inside the bedroom. These results, obtained in an ecological valid setting, support previous laboratory findings that railway noise has a stronger impact than road traffic noise on physiological parameters during sleep, and that the maximum noise level is an important predictor of noise effects on sleep assessed by PSG, at least for railway noise.

  2. Evaluating the effectiveness of active noise reduction in flight helmets

    NASA Astrophysics Data System (ADS)

    Forshaw, S. E.; Rylands, J. M.; Crabtree, R. B.

    1988-08-01

    The advent of high powered fixed- and rotary-wing aircraft and tracked armoured fighting vehicles has increased the level of noise to which crews are exposed. Active noise reduction (ANR) offers a means of increasing the attenuation at low and mid frequencies. It relies on sensing the sound inside a circumaural device and cancelling it by means of negative feedback through a miniature speaker inside the enclosed volume. This study was carried out to investigate laboratory procedures appropriate for measuring the effectiveness of ANR devices. The procedures were: ear-canal measurements using an acoustic test fixture (an objective procedure), and masked threshold and loudness balance tests (psycho-physical procedures). In addition, the effect of ANR on signal detection and speech reception was investigated. The results do not clearly permit one procedure to be recommended for the evaluation of ANR systems. Signal detection performance and speech intelligibility may be used, but the results are specific to the acoustic environment of the listener and the detection task or speech-system parameters of the evaluation. When the attenuation of the ANR system is measured objectively with a transducer inside the earmuff/ear-canal volume, the location of the transducer affects the observed ANR attenuations.

  3. Geometrical Effects in Noise Spectra of Superconducting Flux Qubits

    NASA Astrophysics Data System (ADS)

    Petukhov, Andre; Smelyanskiy, Vadim; Martinis, John

    We present theoretical study of geometrical effects related to spin diffusion in superconducting flux qubits. We adopt a model of a long superconducting wire surrounded by a thin oxide layer with spins distributed uniformly over cross-sectional area of the oxide layer. Using a continuous transformation from a round cylinder to a flat wire strip, we demonstrate that the noise spectral density tends to a power law S (ω) ~(ω / Γ) - s with s 3 / 4 , approaching s = 3 / 4 for very thin wires. The ω-s dependence is valid in a broad frequency range above ωΓ stretching up to four orders of magnitude in units of characteristic diffusion decay rate Γ ~ 1 -102 Hz. The effect is highly sensitive to a cross-sectional aspect ratio of a thin wire thus revealing its geometrical origin. We substantiate our findings by detailed comparison with available experimental data and conclude that 3 / 4 power law distinguishes spin diffusion flux noise from generic `` 1 / f '' family. Supported by the AFRL Information Directorate under Grant F4HBKC4162G001.

  4. Effects of luminance and spatial noise on interferometric contrast sensitivity

    NASA Astrophysics Data System (ADS)

    Coletta, Nancy J.; Sharma, Vineeta

    1995-10-01

    Optical properties of the eye contribute to the reduced visibility of spatial patterns at low luminance. To study the limits of spatial vision when optical factors are minimized, we measured contrast-sensitivity functions (CSF's) for 543.5-nm laser interference fringes imaged directly on the retina. Measurements were made in the fovea at four luminance levels, ranging from 0.3 to 300 photopic trolands (Td). At each luminance the fraction of coherent light in the stimulus pattern was varied to assess the masking effects of laser speckle, which is visible as spatial noise in fields of coherent light. Compared with published CSF's obtained under natural viewing conditions, interferometric CSF's were similar in height but broader, with the range of visibility being extended to higher spatial frequencies. The masking effects of speckle were greatest at the highest luminance and were negligible at the lowest luminance. For low coherent fractions, contrast sensitivity improved over the entire luminance range at a rate consistent with a square-root law; with purely coherent light, sensitivity tended to level off at approximately 30 Td because of speckle masking. The results indicate that the optical quality of the eye reduces the spatial bandwidth of vision even at luminances near the foveal threshold. The change in interference fringe visibility with luminance is consistent with noise-limited behavior, and the masking

  5. The Effect of Cross Flow on Slat Noise

    NASA Technical Reports Server (NTRS)

    Lockard, David P.; Choudhari, Meelan M.

    2010-01-01

    This paper continues the computational examination (AIAA Journal, Vol. 45, No. 9, 2007, pp. 2174-2186) of the unsteady flow within the slat cove region of a multi-element high-lift airfoil configuration. Two simulations have been performed to examine the effect of cross flow on the near-field fluctuations and far-field acoustics. The cross flow was imposed by changing the free-stream velocity vector and modifying the Reynolds number. The cross flow does appear to alter the dynamics in the cove region, but the impact on the noise seems to be more dependent on the flow conditions. However, separating out the true effects of the cross flow from those of the Mach and Reynolds number would require additional calculations to isolate those effects.

  6. [Fundamental and applied aspects of preventing the adverse effects of aviation noise].

    PubMed

    Zhdan'ko, I M; Zinkin, V N; Soldatov, S K; Bogomolov, A V; Sheshegov, P M

    2014-01-01

    In the article, aviation noise is discussed as a harmful physical factor with ecological, hygienic, clinical and social implications. Noise contributes to development of general and occupational pathologies, chronic diseases, and reduction of professional longevity. The present-day knowledge of aviation noise sources and dynamics, and effects on environment, population, and aviation personnel is overviewed, as well as strategies to prevent noise consequences, muffling techniques being the key ones.

  7. Flight effects on exhaust noise for turbojet and turbofan engines: Comparison of experimental data with prediction

    NASA Technical Reports Server (NTRS)

    Stone, J. R.

    1976-01-01

    It was demonstrated that static and in flight jet engine exhaust noise can be predicted with reasonable accuracy when the multiple source nature of the problem is taken into account. Jet mixing noise was predicted from the interim prediction method. Provisional methods of estimating internally generated noise and shock noise flight effects were used, based partly on existing prediction methods and partly on recent reported engine data.

  8. Construction and application of a questionnaire for the social scientific investigation of environmental noise effects

    NASA Technical Reports Server (NTRS)

    Guski, R.; Wichmann, U.; Rohrmann, B.; Finke, H. O.

    1980-01-01

    A social psychological questionnair has been developed to study the effects of environmental noise and was applied to 636 people living in 19 different areas of Hamburg. The theoretical foundations and the statistical means employed in its development are described. Four main reactions to noise are isolated statistically, and it is determined that these are moderated by several intervening variables, chief of which are coping capacity for noise, the perceived dangerousness of the noise souce, other daily loads and the individual's liability.

  9. Effects of noise and parameter deviations in a bichromatic Raman white light cavity

    SciTech Connect

    Sun Qingqing; Zubairy, M. Suhail; Shahriar, M. Selim

    20