Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 19.094
Filtrar
1.
Br J Nurs ; 29(5): 298-302, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32167811

RESUMO

Sleep disturbance is common in patients in the intensive care unit (ICU). Numerous factors can contribute to this. High noise and light levels, nursing interventions and medication administration are major factors. This study investigated the demographic and environmental factors that might adversely affect ICU patients' quality of sleep. Data were collected from 103 patients using a demographic data sheet, the Freedman Quality of Sleep Scale and the Richards-Campbell Sleep Scale. Patients' demographic characteristics were found to have no significant effects on their perceived quality of sleep. Environmental factors, including noise, light, nursing interventions, diagnostic testing, the administration of medication, talking and phones ringing, were significantly related to the patients' perceived quality of sleep.


Assuntos
Unidades de Terapia Intensiva/estatística & dados numéricos , Ruído/efeitos adversos , Transtornos do Sono-Vigília/epidemiologia , Adulto , Cuidados Críticos , Estudos Transversais , Meio Ambiente , Feminino , Humanos , Jordânia , Masculino , Sono/fisiologia , Privação do Sono , Transtornos do Sono-Vigília/etiologia
2.
Environ Monit Assess ; 192(2): 152, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32002686

RESUMO

Noise pollution in urban areas is an emerging environmental threat which local agencies and state authorities must consider in planning and development. Excessive noise is becoming a significant problem adversely affecting the physiological and psychological health of the citizens. Present study was carried out to assess and quantitatively evaluate ambient noise levels in Mumbai Metropolitan Region (MMR) consisting of 9 cities namely Bhiwandi-Nizampur, Kalyan-Dombivli, Mira-Bhayandar, Mumbai, Navi Mumbai, Panvel, Thane, Ulhasnagar and Vasai-Virar. The noise environment was assessed on the basis of equivalent continuous sound pressure levels (Leq), day-night noise levels (LDN) and noise limit exceedance factor (NEF) during day and night time of working and non-working days in four different area categories, viz. industrial, commercial, residential and silence zones. Present study shows that silence zones have been the worst affected areas where noise pollution levels and NEF indicate excessive violation of permissible noise limits due to unplanned, congested and unruly spaces for developmental and commercial activities, followed closely by residential and commercial zones. Cities with separate industrial and commercial zones showed less noisy surroundings in comparison with those cities where land use pattern of industrial and commercial zones is around or overlapping each other. It can thus be concluded that appropriate demarcation and planned use of city space is important to avoid exposure to rising noise pollution levels. Based on the noise pollution in (MMR), various control measures are suggested including awareness campaign and strict compliance of the rules and regulations.


Assuntos
Monitoramento Ambiental , Ruído , Cidades , Poluição Ambiental , Índia , Indústrias
3.
Science ; 367(6476): 364-365, 2020 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-31974233
4.
Mar Pollut Bull ; 150: 110792, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31910530

RESUMO

Pile driving occurs during construction of marine platforms, including offshore windfarms, producing intense sounds that can adversely affect marine animals. We quantified how a commercially and economically important squid (Doryteuthis pealeii: Lesueur 1821) responded to pile driving sounds recorded from a windfarm installation within this species' habitat. Fifteen-minute portions of these sounds were played to 16 individual squid. A subset of animals (n = 11) received a second exposure after a 24-h rest period. Body pattern changes, inking, jetting, and startle responses were observed and nearly all squid exhibited at least one response. These responses occurred primarily during the first 8 impulses and diminished quickly, indicating potential rapid, short-term habituation. Similar response rates were seen 24-h later, suggesting squid re-sensitized to the noise. Increased tolerance of anti-predatory alarm responses may alter squids' ability to deter and evade predators. Noise exposure may also disrupt normal intraspecific communication and ecologically relevant responses to sound.


Assuntos
Decapodiformes , Ruído , Estimulação Acústica , Animais , Ecossistema , Som
5.
Environ Pollut ; 256: 113461, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31706765

RESUMO

OBJECTIVE: Electrohypersensitive people attribute various symptoms to exposure of radiofrequency electromagnetic fields (RF-EMF); sleep disturbance is the most frequently cited. However, laboratory experiments have yielded conflicting results regarding sleep alterations. Our hypothesis was that exposure to RF-EMF alone would lead to slight or non-significant effects but that co-exposure to RF-EMFs and other environmental constraints (such as noise) would lead to significant effects. METHODS: 3-week-old male Wistar rats (4 groups, n = 12 per group) were exposed for 5 weeks to continuous RF-EMF (900 MHz, 1.8 V/m, SAR = 30 mW/kg) in the presence or absence of high-level noise (87.5 dB, 50-20000 Hz) during the rest period. After 5 weeks of exposure, sleep (24 h recording), food and water intakes, and body weight were recorded with or without RF-EMF and/or noise. At the end of this recording period, sleep was scored during the 1 h resttime in the absence of noise and of RF-EMF exposure. RESULTS: Exposure to RF-EMF and/or noise was associated with body weight gain, with hyperphagia in the noise-only and RF-EMF + noise groups and hypophagia in the RF-EMF-only group. Sleep parameters recording over 24 h highlighted a higher frequency of active wakefulness in the RF-EMF-only group and a lower non-rapid eye movement/rapid eye movement sleep ratio during the active period in the noise-only group. There were no differences in sleep duration in either group. During the 1-h, constraint-free sleep recording, sleep rebound was observed in the noise-only group but not in the RF-EMF-only and RF-EMF + noise groups. CONCLUSION: Our study showed effects of RF-EMF, regardless of whether or not the animals were also exposed to noise. However, the RF-EMF + noise group presented no exacerbation of those effects. Our results did not support the hypothesis whereby the effects of RF-EMF on physiological functions studied are only visible in animals exposed to both noise and RF-EMF.


Assuntos
Campos Eletromagnéticos , Ruído , Ondas de Rádio , Animais , Peso Corporal , Ingestão de Alimentos , Exposição Ambiental , Humanos , Masculino , Ratos , Ratos Wistar , Sono/fisiologia
6.
Environ Pollut ; 256: 113314, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31761596

RESUMO

Urbanisation is increasing globally at a rapid pace. Consequently, wild species face novel environmental stressors associated with urban sprawl, such as artificial light at night and noise. These stressors have pervasive effects on the behaviour and physiology of many species. Most studies have singled out the impact of just one of these stressors, while in the real world they are likely to co-occur both temporally and spatially, and we thus lack a clear understanding of the combined effect of anthropogenic stressors on wild species. Here, we experimentally exposed captive male great tits (Parus major) to artificial light at night and 24 h noise in a fully factorial experiment. We then measured the effect of both these stressors on their own and their combination on the amount and timing of activity patterns. We found that both light and noise affected activity patterns when presented alone, but in opposite ways: light increased activity, particularly at night, while noise reduced it, particularly during the day. When the two stressors were combined, we found a synergistic effect on the total activity and the nighttime activity, but an antagonistic effect on daytime activity. The significant interaction between noise and light treatment also differed among forest and city birds. Indeed, we detected a significant interactive effect on light and noise on daytime, nighttime, dusktime and offset of activity of urban birds, but not of forest birds. These results suggest that both artificial light at night and anthropogenic noise can drive changes in activity patterns, but that the specific impacts depend on the habitat of origin. Furthermore, our results demonstrate that co-occurring exposure to noise and light can lead to a stronger impact at night than predicted from the additive effects and thus that multisensory pollution may be a considerable threat for wildlife.


Assuntos
Comportamento Animal/fisiologia , Luz/efeitos adversos , Ruído/efeitos adversos , Aves Canoras/fisiologia , Animais , Animais Selvagens , Ritmo Circadiano/fisiologia , Cidades , Ecossistema , Masculino , Países Baixos , Fotoperíodo , Estações do Ano , Urbanização
7.
HNO ; 68(1): 14-24, 2020 Jan.
Artigo em Alemão | MEDLINE | ID: mdl-31598771

RESUMO

BACKGROUND: Since 2017, the Freiburg monosyllabic speech test can be used in hearing aid evaluation with background noise in Germany. The results are used to compare the aided versus the unaided condition. However, there is currently no reference speech recognition curve for a comparison to listeners with normal hearing. OBJECTIVE: The goal is to establish a reference speech recognition curve for listeners with normal hearing and to analyze the perceptual equivalence of the test lists in continuous CCITT noise (according to Comité Consultatif International Téléphonique et Télégraphique). MATERIALS AND METHODS: The measurements were conducted at two different sites with 90 participants in total. Monosyllables and CCITT noise were presented at different signal-to-noise ratios by one loudspeaker from the front (S0N0). Individual and test-list specific discrimination functions were fitted to differentiate between the sites and among test lists. RESULTS: The reference speech recognition curve and its region of tolerance were established. Three perceptively deviating test lists (1, 3, 20) were identified. CONCLUSION: The reference speech recognition curve enables quantification of hearing difficulties with Freiburg monosyllables in noise and an estimation of the rehabilitation with hearing aids. This reference curve is only valid for frontal stimulus presentation (S0N0) and continuous CCITT noise. Perceptually deviating test lists were different to those in quiet, but partly correspond to literature data.


Assuntos
Auxiliares de Audição , Perda Auditiva , Percepção da Fala , Fala , Alemanha , Humanos , Ruído , Testes de Discriminação da Fala
8.
Environ Pollut ; 256: 113373, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31672366

RESUMO

Comprehensively understanding the factors affecting physiology and fitness in urban wildlife requires concurrently considering multiple stressors. To this end, we simultaneously assessed how metal pollution and proximity to roads affect body condition and telomere shortening between days 8 and 15 of age in nestling great tits (Parus major), a common urban bird. We employed a repeated-measures sampling design to compare telomere shortening and body condition between nestlings from four urban study sites south of Antwerp, Belgium, which are located at different distances from a metal pollution point source. In addition, we explored associations between metal exposure and telomere dynamics on the individual level by measuring blood concentrations of five metals/metalloids, of which lead, copper and zinc were present at concentrations above the limit of detection. To assess whether roadway-associated stressors (e.g. noise and air pollution) might affect nestling condition and telomere shortening, we measured the proximity of nest boxes to roads. Metal exposure was not associated with nestling telomere length or body condition, despite elevated blood lead concentrations close to the metal pollution source (mean ±â€¯SE = 0.270 ±â€¯0.095 µg/g wet weight at the most polluted study site), suggesting that nestlings may have some capacity to detoxify metals. However, nestlings from nest boxes near roads exhibited more telomere shortening between days 8 and 15 of age, and shorter telomeres at day 15. Nestlings in poorer condition also had shorter telomeres, but proximity to the road was unrelated to body condition. Thus, nutritional stress is unlikely to mediate the relationship between proximity to roads and telomere length. Rather, proximity to roads could have affected telomere shortening by exposing nestlings to air or noise pollution. Our study highlights that traffic-related pollution, which is implicated in human health problems, might also affect urban wildlife.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/sangue , Metais Pesados/sangue , Ruído/efeitos adversos , Passeriformes/genética , Encurtamento do Telômero , Animais , Bélgica , Feminino , Masculino , Passeriformes/sangue
9.
Codas ; 31(5): e20170233, 2019.
Artigo em Português, Inglês | MEDLINE | ID: mdl-31721912

RESUMO

PURPOSE: To evaluate preterm infants' exposure and reactions to intense noise during incubator care. METHODS: An observational and prospective study was performed in the intermediary care unit of a hospital in Ribeirão Preto (SP). Thirty-five preterm infants participated in the first stage of the study (measuring noise) and 20 in the second (analysis of responses to intense noise). Noise was measured for two hours using a dosimeter, and the responses were video recorded by three cameras connected to a computer. The preterm infants' responses to an Lmax higher than 65 decibels were analyzed. RESULTS: Every preterm infant presented Leq above the limit recommended by international organizations, and more than half of the babies had a mean Leq above the limit permitted by the Brazilian standard. Regarding the babies' responses to the intense noise, the majority of them showed blink reflex, startle reflex, facial mimics, changed bodily activities or changed sleep and wake state, all with statistically significant differences. CONCLUSION: The sound levels measured were intense. The noises that preterm infants are exposed to while being cared for in incubators constitute a stressor event. Sudden, intense noises change their behavioral state and causes reflexive and bodily responses, facial manifestations and changes in their sleep and wake state.


Assuntos
Incubadoras para Lactentes/efeitos adversos , Recém-Nascido Prematuro , Ruído/efeitos adversos , Feminino , Humanos , Incubadoras para Lactentes/estatística & dados numéricos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Masculino , Estudos Prospectivos
10.
BMC Public Health ; 19(1): 1508, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31718590

RESUMO

BACKGROUND: Noise exposure is considered a stressor that may potentially exert negative health effects among the exposed individuals. On a population basis, the most prevalent and immediate response to noise is annoyance, which is an individually experienced phenomenon that may activate physiological stress-responses and result in both physical and mental symptoms. Health implications of traffic noise have been investigated thoroughly, but not of neighbour noise. The aim of the present study was to examine the associations between neighbour noise annoyance and eight different physical and mental health symptoms. METHODS: Cross-sectional data from the Danish Health and Morbidity Survey 2017 were used. The present study included a random sample of 3893 adults living in multi-storey housing. Information on neighbour noise annoyance and various health symptoms (e.g. pain in various body parts, headache, sleeping problems, depression, and anxiety) during the past two weeks was obtained by self-administered questionnaires. The question on neighbour noise annoyance and health symptoms, respectively, had three possible response options: 'Yes, very annoyed/bothered', 'Yes, slightly annoyed/bothered', 'No'. The associations between neighbour noise annoyance and very bothering physical and mental health symptoms were investigated using multiple logistic regression models. RESULTS: Being very annoyed by neighbour noise was significantly associated with higher odds of being very bothered by all eight health symptoms (adjusted OR = 1.73-3.32, all p-values < 0.05) compared to individuals not annoyed by noise from neighbours. Statistically significant interactions were observed between sex and two of the eight health symptoms. Among women, a strong association was observed between neighbour noise annoyance and being very bothered by pain or discomfort in the shoulder or neck, and in the arms, hands, legs, knees, hips or joints. Among men, no associations were observed. CONCLUSIONS: Based on the findings from this study, neighbour noise annoyance is strongly associated with eight different physical and mental health symptoms. Future studies are encouraged to 1) determine the direction of causality using a longitudinal design, 2) explore the biological mechanisms explaining the sex-specific impact of neighbour noise annoyance on symptoms of musculoskeletal pain or discomfort and the other outcomes as well.


Assuntos
Exposição Ambiental , Habitação , Ruído/efeitos adversos , Características de Residência , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ansiedade/etiologia , Estudos Transversais , Dinamarca , Depressão/etiologia , Feminino , Cefaleia/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Ruído dos Transportes/efeitos adversos , Razão de Chances , Dor/etiologia , Fatores Sexuais , Transtornos do Sono-Vigília/etiologia , Inquéritos e Questionários , Adulto Jovem
11.
Environ Monit Assess ; 191(12): 765, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31754865

RESUMO

To be able to geographically map, model and evaluate noisy sound emissions from industrial motors, emphases have been laid on various phenomena linked to the propagation of sound waves and their effects on the environment. The failure to respect factory-servicing norms coupled with the depreciation of parts of an industrial motor lead to additional sound production, which due to an accumulation in acoustic power and pressure levels contributes to environmental noise pollution. In this work, a study has been carried out on environmental noise pollution from a thermal power plant in Cameroon, using empirical, diagrammatic, analytical and noise map elaboration methods, with the aim of proposing an optimal protection of the surroundings of the thermal plant from the noise pollution. The results obtained show a similarity in propagation of acoustic pressure and power levels for the different types of frequencies considered. Besides these, the study has revealed that the inhabitants are exposed to sound levels higher than the upper limit of 50 dB and above the alert threshold level of 80 dB. At the geo-localized motors of the plant, the primary sources of acoustic power levels were found to fall within the range from 60 to 98 dB, which is very close to the acoustic pressure levels of between 60 and 95 dB. Due to dispersion of sound, the acoustic power levels are also felt at different points around the plant, considered here as secondary sources. From a general point of view, the observed distribution of the iso-sound contours from the collected data and their general NE-SW orientations show the development of new sources due to cumulative effects and superposition of sound waves at regular intervals. At the same time, the acoustic power and pressure levels have been found to be higher than 80 dB, which is the threshold value for human hearing. This therefore is considered detrimental to human health and wellbeing, provoking the need for a more profound investigation on the existing correlation between levels of sound due to stationary sources and frequency in a high sound medium and elaborating a strategic noise map for the town of Mbalmayo and its environs.


Assuntos
Mapeamento Geográfico , Instalações Industriais e de Manufatura , Modelos Teóricos , Ruído , Acústica , Camarões , Monitoramento Ambiental , Instalações Industriais e de Manufatura/estatística & dados numéricos , Centrais Elétricas/estatística & dados numéricos
12.
Biol Lett ; 15(11): 20190649, 2019 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-31744413

RESUMO

Anthropogenic noise has become a major global pollutant and studies have shown that noise can affect animals. However, such single studies cannot provide holistic quantitative assessments on the potential effects of noise across species. Using a multi-level phylogenetically controlled meta-analysis, we provide the first holistic quantitative analysis on the effects of anthropogenic noise. We found that noise affects many species of amphibians, arthropods, birds, fish mammals, molluscs and reptilians. Interestingly, phylogeny contributes only little to the variation in response to noise. Thus, the effects of anthropogenic noise can be explained by the majority of species responding to noise rather than a few species being particularly sensitive to noise. Consequently, anthropogenic noise must be considered as a serious form of environmental change and pollution as it affects both aquatic and terrestrial species. Our analyses provide the quantitative evidence necessary for legislative bodies to regulate this environmental stressor more effectively.


Assuntos
Aves , Ruído , Anfíbios , Animais , Peixes , Mamíferos
13.
Environ Sci Pollut Res Int ; 26(36): 36812-36819, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31745771

RESUMO

Noise is one of the most significant sources of environmental pollution in metro cities. Traffic noise plays an important role to contribute to ambient noise pollution. Noise pollution monitoring was carried out using sound level meter mounted on the cycle with the help of mould fixed on it. Cycle is a noiseless mode of transport and therefore, it was used for noise monitoring over 700 locations in Nagpur City. Noise levels were recorded at each location for 5 min during peak rush hours of traffic in the morning and in the evening at an interval of 1 s leading to around 300 readings each. Noise indices like Leq, L90, L10, Lmax and Lmin were calculated for noise level data analysis. TNI was also determined for analysis of traffic noise on intersections of roads. Equivalent noise levels were transferred into the Geographic Information System (GIS) and spatial analysis tool was used to create spatial and strategic noise maps. Based on the maps, it is revealed that noise levels are exceeded all over the city with respect to ambient noise standards. It was experienced that intersections of roads during peak rush time are very noisy due to honking. The study recommends the noise monitoring through cycle-mounted sound level meter since it covers unapproachable sites, more coverage in the city that helps in identifying hotspot area of concern for noise abatement strategies and planning.


Assuntos
Monitoramento Ambiental , Ruído , Cidades , Poluição Ambiental , Índia , Análise Espacial
14.
Biol Lett ; 15(10): 20190513, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31662064

RESUMO

Although the effects of anthropogenic noise on animal communication have been studied widely, most research on the effect of noise in communication has focused on signals in a single modality. Consequently, how multi-modal communication is affected by anthropogenic noise is relatively poorly understood. Here, we ask whether song sparrows (Melospiza melodia) show evidence of plasticity in response to noise in two aggressive signals in acoustic and visual modalities. We test two hypotheses: (i) that song sparrows will shift signalling effort to the visual modality (the multi-modal shift hypothesis) and (ii) that they will increase redundancy of their multi-modal signalling (the back-up signal hypothesis). We presented male song sparrows with song playback and a taxidermic mount with or without a low-frequency acoustic noise from a nearby speaker. We found that males did not switch their signalling effort to visual modality (i.e. wing waves) in response to the noise. However, the correlation between warbled soft songs and wing waves increased in the noise treatment, i.e. signals became more redundant. These results suggest that when faced with anthropogenic noise, song sparrows can increase the redundancy of their multi-modal signals, which may aid in the robustness of the communication system.


Assuntos
Pardais , Acústica , Comunicação Animal , Animais , Masculino , Ruído , Vocalização Animal
15.
Brain Lang ; 199: 104699, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31569040

RESUMO

Listening to white noise may facilitate cognitive performance, including new word learning, for some individuals. This study investigated whether auditory white noise facilitates the learning of novel written words from context in healthy young adults. Sixty-nine participants were required to determine the meaning of novel words placed within sentence contexts during a silent reading task. Learning was performed either with or without white noise, and recognition of novel word meanings was tested immediately after learning and after a short delay. Immediate recognition accuracy for learned novel word meanings was higher in the noise group relative to the no noise group, however this effect was no longer evident at the delayed recognition test. These findings suggest that white noise has the capacity to facilitate meaning acquisition from context, however further research is needed to clarify its capacity to improve longer-term retention of meaning.


Assuntos
Ruído , Leitura , Aprendizagem Verbal/fisiologia , Estimulação Acústica , Percepção Auditiva , Feminino , Humanos , Masculino , Adulto Jovem
16.
Codas ; 31(5): e20180217, 2019.
Artigo em Português, Inglês | MEDLINE | ID: mdl-31644717

RESUMO

PURPOSE: To compare the ability to recognize sentences in silence and in noise in monolingual normal-hearing Brazilian Portuguese speakers, and bilingual speakers of Brazilian Portuguese and German, and bilingual speakers of Brazilian Portuguese and Italian, as well as to analyze the influence of age of second language acquisition on the performance of bilinguals. METHODS: 87 normal-hearing individuals aged between 18 and 55 years participated of this research. They were categorized into: Control Group, composed by 30 monolingual Brazilian Portuguese speakers; German Research Group, 31 simultaneous bilingual native speakers of Portuguese and speakers of German as a second language and; Italian Research Group, consisting of 26 successive bilinguals, native speakers of Portuguese and speakers of Italian as a second language. The Sentence List Test in Brazilian Portuguese was used to measure their Sentence Recognition Thresholds in Silence and Noise. RESULTS: In silence, there were no statistically significant differences in performance when comparing the bilingual to the monolingual individuals, and when comparing the bilingual speakers among themselves. On the other hand, in noise, there was a significant difference between the bilingual groups and the monolingual one. However, there were no significant differences between the bilingual groups when their performance was compared. CONCLUSION: Bilingualism positively influenced the development of language and listening skills, which led the bilinguals to outperform in speech recognition in the presence of noise. Also, the period of a second language acquisition did not influence bilingual performance.


Assuntos
Multilinguismo , Ruído , Percepção da Fala/fisiologia , Adolescente , Adulto , Estudos de Casos e Controles , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Teste do Limiar de Recepção da Fala , Adulto Jovem
17.
Philos Trans A Math Phys Eng Sci ; 377(2159): 20190070, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31607251

RESUMO

The extended introduction in this paper reviews the theoretical modelling of leading- and trailing-edge noise, various bioinspired aerofoil adaptations to both the leading and trailing edges of blades, and how these adaptations aid in the reduction of aerofoil-turbulence interaction noise. Attention is given to the agreement between current theoretical predictions and experimental measurements, in particular, for turbulent interactions at the trailing edge of an aerofoil. Where there is a poor agreement between theoretical models and experimental data the features neglected from the theoretical models are discussed. Notably, it is known that theoretical predictions for porous trailing-edge adaptations do not agree well with experimental measurements. Previous works propose the reason for this: theoretical models do not account for surface roughness due to the porous material and thus omit a key noise source. The remainder of this paper, therefore, presents an analytical model, based upon the acoustic analogy, to predict the far-field noise due to a rough surface at the trailing edge of an aerofoil. Unlike previous roughness noise models which focus on roughness over an infinite wall, the model presented here includes diffraction by a sharp edge. The new results are seen to be in better agreement with experimental data than previous models which neglect diffraction by an edge. This new model could then be used to improve theoretical predictions for far-field noise generated by turbulent interactions with a (rough) porous trailing edge. This article is part of the theme issue 'Frontiers of aeroacoustics research: theory, computation and experiment'.


Assuntos
Biomimética/métodos , Modelos Teóricos , Ruído , Porosidade , Propriedades de Superfície
18.
Sensors (Basel) ; 19(20)2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615138

RESUMO

Simultaneous recordings of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) are at the forefront of technologies of interest to physicians and scientists because they combine the benefits of both modalities-better time resolution (hdEEG) and space resolution (fMRI). However, EEG measurements in the scanner contain an electromagnetic field that is induced in leads as a result of gradient switching slight head movements and vibrations, and it is corrupted by changes in the measured potential because of the Hall phenomenon. The aim of this study is to design and test a methodology for inspecting hidden EEG structures with respect to artifacts. We propose a top-down strategy to obtain additional information that is not visible in a single recording. The time-domain independent component analysis algorithm was employed to obtain independent components and spatial weights. A nonlinear dimension reduction technique t-distributed stochastic neighbor embedding was used to create low-dimensional space, which was then partitioned using the density-based spatial clustering of applications with noise (DBSCAN). The relationships between the found data structure and the used criteria were investigated. As a result, we were able to extract information from the data structure regarding electrooculographic, electrocardiographic, electromyographic and gradient artifacts. This new methodology could facilitate the identification of artifacts and their residues from simultaneous EEG in fMRI.


Assuntos
Algoritmos , Artefatos , Eletroencefalografia , Imagem por Ressonância Magnética , Dinâmica não Linear , Eletroculografia , Humanos , Ruído
19.
Nat Commun ; 10(1): 4592, 2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31597928

RESUMO

Across vertebrates, progressive changes in vocal behavior during postnatal development are typically attributed solely to developing neural circuits. How the changing body influences vocal development remains unknown. Here we show that state changes in the contact vocalizations of infant marmoset monkeys, which transition from noisy, low frequency cries to tonal, higher pitched vocalizations in adults, are caused partially by laryngeal development. Combining analyses of natural vocalizations, motorized excised larynx experiments, tensile material tests and high-speed imaging, we show that vocal state transition occurs via a sound source switch from vocal folds to apical vocal membranes, producing louder vocalizations with higher efficiency. We show with an empirically based model of descending motor control how neural circuits could interact with changing laryngeal dynamics, leading to adaptive vocal development. Our results emphasize the importance of embodied approaches to vocal development, where exploiting biomechanical consequences of changing material properties can simplify motor control, reducing the computational load on the developing brain.


Assuntos
Callithrix/fisiologia , Laringe/fisiologia , Prega Vocal/fisiologia , Vocalização Animal/fisiologia , Algoritmos , Animais , Animais Recém-Nascidos , Callithrix/crescimento & desenvolvimento , Feminino , Laringe/crescimento & desenvolvimento , Masculino , Modelos Biológicos , Ruído , Som , Prega Vocal/crescimento & desenvolvimento
20.
PLoS Comput Biol ; 15(10): e1007430, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31626624

RESUMO

Perception of vocalizations and other behaviorally relevant sounds requires integrating acoustic information over hundreds of milliseconds. Sound-evoked activity in auditory cortex typically has much shorter latency, but the acoustic context, i.e., sound history, can modulate sound evoked activity over longer periods. Contextual effects are attributed to modulatory phenomena, such as stimulus-specific adaption and contrast gain control. However, an encoding model that links context to natural sound processing has yet to be established. We tested whether a model in which spectrally tuned inputs undergo adaptation mimicking short-term synaptic plasticity (STP) can account for contextual effects during natural sound processing. Single-unit activity was recorded from primary auditory cortex of awake ferrets during presentation of noise with natural temporal dynamics and fully natural sounds. Encoding properties were characterized by a standard linear-nonlinear spectro-temporal receptive field (LN) model and variants that incorporated STP-like adaptation. In the adapting models, STP was applied either globally across all input spectral channels or locally to subsets of channels. For most neurons, models incorporating local STP predicted neural activity as well or better than LN and global STP models. The strength of nonlinear adaptation varied across neurons. Within neurons, adaptation was generally stronger for spectral channels with excitatory than inhibitory gain. Neurons showing improved STP model performance also tended to undergo stimulus-specific adaptation, suggesting a common mechanism for these phenomena. When STP models were compared between passive and active behavior conditions, response gain often changed, but average STP parameters were stable. Thus, spectrally and temporally heterogeneous adaptation, subserved by a mechanism with STP-like dynamics, may support representation of the complex spectro-temporal patterns that comprise natural sounds across wide-ranging sensory contexts.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Estimulação Acústica , Potenciais de Ação/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Feminino , Furões , Masculino , Modelos Neurológicos , Modelos de Interação Espacial , Plasticidade Neuronal , Neurônios/fisiologia , Ruído , Som
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA