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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Passive Acoustic Studies of Estuarine Fish Populations of Southwest Florida

Locascio, James Vincent 25 February 2010 (has links)
Recordings of fish sound production were made in Charlotte Harbor, Florida using Long Term Acoustic Recording Systems (LARS) programmed to record 10 seconds of sound every 10 minutes. Results demonstrated a strong circadian pattern in fish sound production that occurred within a few hours of dusk each evening. Sound production lasted on average 8.7 hrs each evening during the peak spawning season. LARS were deployed when Hurricane Charley crossed Charlotte Harbor in August, 2004. The hurricane did not inhibit nightly chorusing events of spawning fish. Rather, sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane. Acoustic time series data recorded at multiple sites in Charlotte Harbor during 2005 revealed changes in the spatial distribution of fish sound production in response to increased freshwater inflow and consequent decreased bottom dissolved oxygen concentrations in early June. Fish sound production decreased rapidly over several days at study sites in the northern portion of the harbor most immediately affected by changes in environmental conditions. Meanwhile, fish sound production increased at the study site furthest seaward where normoxic levels were sustained. By August levels of fresh water inflow decreased substantially, bottom dissolved oxygen levels increased and sound production resumed at sites previously affected by these conditions. Fish sound production began intermittently in February and ended in November. Peak levels were reached by mid-late April / early May and continued throughout the summer time. Seasonal patterns of sound production match the reported spawning periods of estuarine sciaenid species recorded. Black drum sound production was measured in the canal systems of Cape Coral and Punta Gorda, Florida during the 2004-2006 spawning seasons. The circadian pattern of sound production was similar to other sciaenids documented in Charlotte Harbor. Seasonal patterns of black drum sound production occurred during October through April and peaked in February. This seasonal period of sound production also matched patterns of black drum reproductive readiness and spawning reported in the literature for the Gulf of Mexico. A hydrophone array was used in the Cape Coral canal system to localize calling black drum and measure source levels and propagation of calls. Source level estimates averaged 165 dBRMS re: 1muPa SPL (SD=1.0) (n = 1,025). Call energy was concentrated in the fundamental frequency (94 Hz) and first two harmonics (188 Hz and 282 Hz). A square root model best described propagation of the fundamental frequency and first harmonic and a log 10 model best described the second harmonic. Based on the mean RMS source level, signal propagation, background levels, and hearing sensitivity, the communication range of black drum at the study site was estimated at between 33 and 108 meters and was limited by background levels, not auditory sensitivity. The timing and levels of sound production and egg production were compared in black drum. Eggs were collected hourly from 1800 - 0400 by surface plankton tows on two consecutive evenings while black drum sound production was continuously recorded. This sampling effort was conducted five separate times from January through April, 2006. Evidence of the time of spawning was indicated by the collection of blastodiscs (fertilized single cell eggs) or back calculated early cleavage stage eggs. Neither the timing nor the quantity of sound production was positively correlated with egg production on a nightly basis and the greatest densities of eggs were collected on evenings which had the lowest levels of sound production. This may have been due to differences in the fecundity of individual females spawning on the evenings when sampling was conducted.
52

The acoustic behavior of the thirteen-lined ground squirrel Citellus tridecemlineatus /

Lishak, Robert Stephen January 1976 (has links)
No description available.
53

DEPTH AND DEVELOPMENT OF THE SONIC SYSTEM IN DEEP-SEA MACROURID FISHES ON THE CONTINENTAL SLOPE

Wrenn, Jonothan 01 January 2016 (has links)
Work on sound production of deep-sea fishes has been limited to anatomy, and no sounds from identified species have been recorded on the continental slope. Here I examined the sonic muscles of six species in the family Macrouridae by depth (Coelorhincus carminatus, Nezumia bairdii, Coryphaenoides rupestris, Nezumia equalis, Coryphaenoides armatus, Coryphaenoides carapinus,). Due to increasingly limited food with depth, I hypothesized that sonic muscle development would decrease with depth. Sonic muscles were intrinsic and occurred in males and females. Swimbladder and sonic muscle dimensions increased linearly with fish size, but there were no clear differences with depth suggesting sound production remains important in deeper species.
54

Phylogenetic Relationships and Character Evolution of the Neotropical Butterfly Genus Hamadryas (Nymphalidae: Biblidinae)

Garzon, Ivonne J. 18 May 2012 (has links)
The butterflies in the genus Hamadryas are popular and noticeable representatives of the Neotropical Lepidoptera fauna. After a thorough taxonomic revision, 20 species were acknowledged within the genus, however no hypothesis of their phylogenetic relationship was proposed. The present dissertation provides a step further into the understanding of this fascinating group of butterflies not only by proposing the first phylogenetic hypothesis for the genus based on morphological and molecular data, but also by exploring for the first time in a group of butterflies the potential effect of venation associated with an specific behaviour on wing shape. Furthermore, this dissertation provides testable evolutionary hypotheses about the pattern of change for some of their most interesting natural history characters such as sound production and sexual dimorphism. The dissertation is organized in three chapters that can be visualized as manuscripts ready for publication; the first of these being already published (Garzón-Orduña, 2012).
55

Acoustic Tonal and Vector Properties of Red Hind Grouper Vocalizationd

Unknown Date (has links)
Vertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical ocean conditions. This configuration allows for what is understood to be omnidirectional projection of tones approximately centered between 40 and 440 Hz and spanning anywhere from 40 to 200 Hz of bandwidth and modulation effects based on observed data provided by researchers. Prior studies on many other fish show correlation in acoustic communication profile with length, size and sexual identity. In the red hind, sexual dimorphism leads to an inherent female identity in all juvenile fish which converts to male according to environmental factors, recommending at least consistent organs across both sexes be assumed even if not in use. Much research has been performed on male fish vocalization in terms of spectral content. Communication in fish is a complex multi-modal process, with acoustic communication being important for many of the species, particularly those in the littoral regions of the worlds’ oceans. If identifying characteristics of the red hind vocalization can be isolated based on detection, classification, tracking and localizing methodologies, then these identifying characteristics may indeed lead to passive feature identification that allows for estimation of individual fish mass. Hypotheses based on vector, cyclostationary and classical tonal mechanics are presented for consideration. A battery of test data collection events, applying pre-recorded fish vocalizations to a geolocated undersea sound source were conducted. The results are supplied with the intent of validating hypothesis in a non-expert system manner that shows how a series of biological metrics may be assessed for detection, classification, localization and mass estimation for an individual vocalizing red hind grouper / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
56

Avian musing feature space analysis

Colón, Guillermo J. 24 May 2012 (has links)
The purpose of this study was to analyze the possibility of utilizing known signal processing and machine learning algorithms to correlate environmental data to chicken vocalizations. The specific musing to be analyzed consist of not just one chicken's vocalizations but of a whole collective, it therefore becomes a chatter problem. There have been similar attempts to create such a correlation in the past but with singled out birds instead of a multitude. This study was performed on broiler chickens (birds used in meat production). One of the reasons why this correlation is useful is for the purpose of an automated control system. Utilizing the chickens own vocalization to determine the temperature, the humidity, the levels of ammonia among other environmental factors, reduces, and might even remove, the need for sophisticated sensors. Another factor that this study wanted to correlate was stress in the chickens to their vocalization. This has great implications in animal welfare, to guarantee that the animals are being properly take care off. Also, it has been shown that the meat of non-stressed chickens is of much better quality than the opposite. The audio was filtered and certain features were extracted to predict stress. The features considered were loudness, spectral centroid, spectral sparsity, temporal sparsity, transient index, temporal average, temporal standard deviation, temporal skewness, and temporal kurtosis. In the end, out of all the features analyzed it was shown that the kurtosis and loudness proved to be the best features for identifying stressed birds in audio.
57

Perceptual sound field synthesis concept for music presentation

Ziemer, Tim 24 April 2020 (has links)
A perceptual sound field synthesis approach for music is presented. Its signal processing implements critical bands, the precedence effect and integration times of the auditory system by technical means, as well as the radiation characteristics of musical instruments. Furthermore, interaural coherence, masking and auditory scene analysis principles are considered. As a result, the conceptualized sound field synthesis system creates a natural, spatial sound impression for listeners in extended listening area, even with a low number of loudspeakers. A novel technique, the “precedence fade”, as well as the interaural cues provided by the sound field synthesis approach, allow for a precise and robust localization.Simulations and a listening test provide a proof of concept. The method is particularly robust for signals with impulsive attacks and long quasi-stationary phases, as in the case of many instrumental sounds. It is compatible with many loudspeaker setups, such as 5.1 to 22.2, ambisonics systems and loudspeaker arrays for wave front synthesis. The perceptual sound field synthesis approach is an alternative to physically centered wave field synthesis concepts and conventional, perceptually motivated stereophonic sound and benefits from both paradigms.
58

Amphibian communication: Coupling of acoustic systems to the medium at the air-water interface

Tang, Justine Nicole 01 January 2016 (has links)
Sound does not transmit well across the interface of two media. Therefore, most organisms communicate using one medium. Some anurans vocalize at the interface of air and water, though reception of these vocalizations is generally unknown. The túngara frog ( Engystomops pustulosus ) may be the first anuran to have evidence suggesting simultaneous acoustic communication both above and below the air-water interface. This thesis addresses whether the female túngara frog would be receptive to underwater acoustic signals and if males project their advertisement calls at biologically relevant intensities underwater. Females floated and swam with their eardrums and body walls constantly submerged. Using laser Doppler vibrometry, peak vibrations of female eardrums were found to be centered at about 3.5 kHz in air, but dropped to about 1.4 kHz underwater. The peak velocity of the eardrum was about 0.2 mm/s in air and 0.04 mm/s in water when stimulated with tones at 80 dB relative to 20 µPa. Males projected their advertisement calls with a sound pressure level of 121 dB (at 10 cm, re. 20 µPa) in water and 98 dB (at 10 cm, re. 20 µPa) in air. In relation to air, the dominant frequency of the advertisement call (0.8 kHz) was the most intense spectral band underwater whereas the dominant frequency of the chuck (2.5 kHz in air) was less intense. The advertisement signal for the male túngara frog was broadcasted underwater with more energy than in air at its main frequencies. Female eardrums were sensitive to frequencies within the male advertisement call both in air and in water, if the frequencies were transmitted at amplitudes plausible to be encountered in nature. These results strengthen the available evidence of underwater communication, and indicate the presence of auditory specializations in the acoustic communication of this species.
59

Variation in sperm whale (Physeter macrocephalus) coda vocalizations and social structure in the North Atlantic Ocean

Antunes, Ricardo January 2009 (has links)
This study aimed at complementing studies of sperm whale social and vocal behaviour that were restricted to the Pacific Ocean. The characteristic multi-pulsed structure of sperm whale clicks allows for estimation of whales' size from measurements of the inter-pulse intervals (IPI). I have developed two new automatic methods for IPI estimation from clicks recorded during foraging dives. When compared to other previously developed methods, the newly developed method that averages several clicks' autocorrelation function showed the best performance amongst the automatic methods. Previous studies did not support individual identity advertisement among social unit members as the function for the sperm whale communication signals called codas. I tested within coda type variation for individual specific patterns and found that, while some coda types do not allow for individual discrimination, one did so. This variation suggests that different coda types may have distinct functions. Analysis of social structure in the Azores found that, similar to the Eastern Tropical Pacific, sperm whales form long term social units of about 12 individuals. Unlike the Pacific Ocean, Azorean social units do not form temporary groups with other units, suggesting differences in the costs and benefits of group formation. I argue that these are due to differences in terms of predation pressure and intraspecific competition between the Azores and the Pacific study sites. The variation of coda repertoires in the Atlantic also showed a pattern dissimilar to that previously documented in the Eastern Tropical Pacific. In the North Atlantic, coda repertoire variation is mostly geographic, which is parsimoniously explained by random drift of culturally transmitted coda repertoires. No sympatric vocal clans with distinct dialects were found as has been noted in the Pacific. Drawing upon the differences found in social structure I argue that selection for maximization of differences between units with similar foraging strategies may have led to the Pacific vocal clans. The differences between oceans suggest that sperm whales may adaptively adjust their behaviour according to experienced ecological conditions.
60

Langage et apprentissage en éducation musicale à l'école et en formation professionnelle : un exemple dans une situation de production sonore et d’analyse auditive / Language and learning in musical education at school and in vocational training : an example in a situation of sound production and hearing analysis

Suissa, Dédé 12 December 2016 (has links)
A l’heure actuelle, des didacticiens des diverses disciplines s’interrogent sur les pratiqueslangagières mises en oeuvre pour penser, pour négocier des significations et stabiliser dessavoirs au sein des contextes scolaires (Jaubert, Rebière). Participant à cette recherche enéducation musicale, l’objet de cette étude porte sur l’analyse de « l’outil » langage (oral etécrit), à la fois linguistique et musical, dans l’acquisition des connaissances des élèves del'école et/ou des étudiants pour le professorat des écoles. Il s’inscrit dans une perspectivehistorique et culturelle, qui voit dans le langage un outil de conceptualisation. / At the moment, didacticiens of the diverse disciplines wonders about the linguistic practicesoperated to think, to negotiate meanings and stabilize knowledges within the school contexts(Jaubert, Rebière). Participating in this research in musical education, the object of thisstudy concerns the analysis of " the tool " language (oral and paper), at the same timelinguistic and musical, in the acquisition of the knowledge of the pupils of the school and thestudents for the teaching profession of schools. It joins in a historical and culturalperspective, which sees in the language a tool of conceptualization.

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