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Search Results: 1 - 10 of 256 matches for " Annemarie Surlykke "
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Probing the Natural Scene by Echolocation in Bats
Cynthia F. Moss,Annemarie Surlykke
Frontiers in Behavioral Neuroscience , 2010, DOI: 10.3389/fnbeh.2010.00033
Abstract: Bats echolocating in the natural environment face the formidable task of sorting signals from multiple auditory objects, echoes from obstacles, prey, and the calls of conspecifics. Successful orientation in a complex environment depends on auditory information processing, along with adaptive vocal-motor behaviors and flight path control, which draw upon 3-D spatial perception, attention, and memory. This article reviews field and laboratory studies that document adaptive sonar behaviors of echolocating bats, and point to the fundamental signal parameters they use to track and sort auditory objects in a dynamic environment. We suggest that adaptive sonar behavior provides a window to bats’ perception of complex auditory scenes.
Echolocating Bats Cry Out Loud to Detect Their Prey
Annemarie Surlykke, Elisabeth K. V. Kalko
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002036
Abstract: Echolocating bats have successfully exploited a broad range of habitats and prey. Much research has demonstrated how time-frequency structure of echolocation calls of different species is adapted to acoustic constraints of habitats and foraging behaviors. However, the intensity of bat calls has been largely neglected although intensity is a key factor determining echolocation range and interactions with other bats and prey. Differences in detection range, in turn, are thought to constitute a mechanism promoting resource partitioning among bats, which might be particularly important for the species-rich bat assemblages in the tropics. Here we present data on emitted intensities for 11 species from 5 families of insectivorous bats from Panamá hunting in open or background cluttered space or over water. We recorded all bats in their natural habitat in the field using a multi-microphone array coupled with photographic methods to assess the bats' position in space to estimate emitted call intensities. All species emitted intense search signals. Output intensity was reduced when closing in on background by 4–7 dB per halving of distance. Source levels of open space and edge space foragers (Emballonuridae, Mormoopidae, Molossidae, and Vespertilionidae) ranged between 122–134 dB SPL. The two Noctilionidae species hunting over water emitted the loudest signals recorded so far for any bat with average source levels of ca. 137 dB SPL and maximum levels above 140 dB SPL. In spite of this ten-fold variation in emitted intensity, estimates indicated, surprisingly, that detection distances for prey varied far less; bats emitting the highest intensities also emitted the highest frequencies, which are severely attenuated in air. Thus, our results suggest that bats within a local assemblage compensate for frequency dependent attenuation by adjusting the emitted intensity to achieve comparable detection distances for prey across species. We conclude that for bats with similar hunting habits, prey detection range represents a unifying constraint on the emitted intensity largely independent of call shape, body size, and close phylogenetic relationships.
Echolocation intensity and directionality of perching and flying fringe-lipped bats, Trachops cirrhosus (Phyllostomidae)
Annemarie Surlykke,Lasse Jakobsen,Rachel A. Page
Frontiers in Physiology , 2013, DOI: 10.3389/fphys.2013.00143
Abstract: The Neotropical frog-eating bat, Trachops cirrhosus, primarily hunts stationary prey, either by gleaning on the wing, or in a sit-and-wait mode hanging from a perch. It listens passively for prey-generated sounds, but uses echolocation in all stages of the hunt. Like other bats in the family Phyllostomidae, T. cirrhosus has a conspicuous nose leaf, hypothesized to direct and focus echolocation calls emitted from the nostrils. T. cirrhosus is highly flexible in its cognitive abilities and its use of sensory strategies for prey detection. Additionally, T. cirrhosus has been observed to echolocate both with closed and open mouth. We hypothesize that its flexibility extends to echolocation call design. We investigated the effect of hunting mode, perching or flying, as well as the effect of mouth opening, on the acoustic parameters and directionality of the echolocation call. We used a multi-microphone array, a high-speed video camera, and a microphone-diode-video system to directly visualize the echolocation sound beam synchronized with the bat's behavior. We found that T. cirrhosus emits a highly directional sound beam with half amplitude angle (HAM) of 12–18° and DI (directionality index) of ~17 dB, among the most directional bat sonar beams measured to date. The directionality was high both when flying and when perching. The emitted intensity was low, around 88 dB SPL at 10 cm from the mouth, when hanging, but higher, around 100 dB SPL at 10 cm, when flying or just before take-off. Our data suggests that the limited search volume of T. cirrhosus sonar beam defined by the high directionality and the rather low intensity of its echolocation calls is adapted to the highly cluttered hunting habitat and to the perch hunting mode.
Intensity and directionality of bat echolocation signals
Lasse Jakobsen,Signe Brinkl?v,Annemarie Surlykke
Frontiers in Physiology , 2013, DOI: 10.3389/fphys.2013.00089
Abstract: The paper reviews current knowledge of intensity and directionality of bat echolocation signals. Recent studies have revealed that echolocating bats can be much louder than previously believed. Bats previously dubbed “whispering” can emit calls with source levels up to 110 dB SPL at 10 cm and the louder open space hunting bats have been recorded at above 135 dB SPL. This implies that maximum emitted intensities are generally 30 dB or more above initial estimates. Bats' dynamic control of acoustic features also includes the intensity and directionality of their sonar calls. Aerial hawking bats will increase signal directionality in the field along with intensity thus increasing sonar range. During the last phase of prey pursuit, vespertilionid bats broaden their echolocation beam considerably, probably to counter evasive maneuvers of eared prey. We highlight how multiple call parameters (frequency, duration, intensity, and directionality of echolocation signals) in unison define the search volume probed by bats and in turn how bats perceive their surroundings. Small changes to individual parameters can, in combination, drastically change the bat's perception, facilitating successful navigation and food acquisition across a vast range of ecological niches. To better understand the function of echolocation in the natural habitat it is critical to determine multiple acoustic features of the echolocation calls. The combined (interactive) effects, not only of frequency and time parameters, but also of intensity and directionality, define the bat's view of its acoustic scene.
Active Listening for Spatial Orientation in a Complex Auditory Scene
Cynthia F. Moss,Kari Bohn,Hannah Gilkenson,Annemarie Surlykke
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0040079
Abstract: To successfully negotiate a complex environment, an animal must control the timing of motor behaviors in coordination with dynamic sensory information. Here, we report on adaptive temporal control of vocal–motor behavior in an echolocating bat, Eptesicus fuscus, as it captured tethered insects close to background vegetation. Recordings of the bat's sonar vocalizations were synchronized with high-speed video images that were used to reconstruct the bat's three-dimensional flight path and the positions of target and vegetation. When the bat encountered the difficult task of taking insects as close as 10–20 cm from the vegetation, its behavior changed significantly from that under open room conditions. Its success rate decreased by about 50%, its time to initiate interception increased by a factor of ten, and its high repetition rate “terminal buzz” decreased in duration by a factor of three. Under all conditions, the bat produced prominent sonar “strobe groups,” clusters of echolocation pulses with stable intervals. In the final stages of insect capture, the bat produced strobe groups at a higher incidence when the insect was positioned near clutter. Strobe groups occurred at all phases of the wingbeat (and inferred respiration) cycle, challenging the hypothesis of strict synchronization between respiration and sound production in echolocating bats. The results of this study provide a clear demonstration of temporal vocal–motor control that directly impacts the signals used for perception.
Active Listening for Spatial Orientation in a Complex Auditory Scene
Cynthia F Moss ,Kari Bohn,Hannah Gilkenson,Annemarie Surlykke
PLOS Biology , 2006, DOI: 10.1371/journal.pbio.0040079
Abstract: To successfully negotiate a complex environment, an animal must control the timing of motor behaviors in coordination with dynamic sensory information. Here, we report on adaptive temporal control of vocal–motor behavior in an echolocating bat, Eptesicus fuscus, as it captured tethered insects close to background vegetation. Recordings of the bat's sonar vocalizations were synchronized with high-speed video images that were used to reconstruct the bat's three-dimensional flight path and the positions of target and vegetation. When the bat encountered the difficult task of taking insects as close as 10–20 cm from the vegetation, its behavior changed significantly from that under open room conditions. Its success rate decreased by about 50%, its time to initiate interception increased by a factor of ten, and its high repetition rate “terminal buzz” decreased in duration by a factor of three. Under all conditions, the bat produced prominent sonar “strobe groups,” clusters of echolocation pulses with stable intervals. In the final stages of insect capture, the bat produced strobe groups at a higher incidence when the insect was positioned near clutter. Strobe groups occurred at all phases of the wingbeat (and inferred respiration) cycle, challenging the hypothesis of strict synchronization between respiration and sound production in echolocating bats. The results of this study provide a clear demonstration of temporal vocal–motor control that directly impacts the signals used for perception.
Variation in Courtship Ultrasounds of Three Ostrinia Moths with Different Sex Pheromones
Takuma Takanashi,Ryo Nakano,Annemarie Surlykke,Haruki Tatsuta,Jun Tabata,Yukio Ishikawa,Niels Skals
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013144
Abstract: Moths use ultrasounds as well as pheromones for sexual communication. In closely related moth species, variations in ultrasounds and pheromones are likely to profoundly affect mate recognition, reproductive isolation, and speciation. The European corn borer, Ostrinia nubilalis, and its Asian congeners, Ostrinia furnacalis and Ostrinia scapulalis, exhibit within-species and between-species variation in their pheromone communication. Recently, we reported ultrasound communication in O. furnacalis; however, variations in ultrasounds in the three congeners have not been addressed to date. Here we investigated features of ultrasound production and hearing in O. nubilalis and O. scapulalis, and compared them with those of O. furnacalis. As in O. furnacalis, males of O. nubilalis and O. scapulalis produced ultrasounds during courtship by rubbing specialized scales on the wings against scales on the thorax. The covering of these scales with nail polish muffled the sounds and significantly reduced mating success in O. nubilalis, showing the importance of ultrasound signaling in mating. The ultrasounds produced by O. nubilalis and O. scapulalis were similar, consisting of long trains of pairs of pulses with a main energy at 40 kHz, but distinctly different from the ultrasound produced by O. furnacalis, consisting of groups of pulses peaking at 50 kHz and with substantially more energy up to 80 kHz. Despite overall similarities, temporal features and patterns of amplitude modulation differed significantly among the geographic populations of O. nubilalis and O. scapulalis, which differed in pheromone type. In contrast, no significant difference in hearing was found among the three species with regard to the most sensitive frequencies and hearing threshold levels. The patterns of variations in the songs and pheromones well reflected those of the phylogenetic relationships, implying that ultrasound and pheromone communications have diverged concordantly. Our results suggest that concordant evolution in sexual signals such as courtship ultrasounds and sex pheromones occurs in moths.
The Effectiveness of a Structured Remediation Program to Pass the NCLEX-RN Examination  [PDF]
Fran Cherkis, Annemarie Rosciano
Open Journal of Nursing (OJN) , 2015, DOI: 10.4236/ojn.2015.53025
Abstract: The National Council Licensure Examination for Registered Nurses (NCLEX-RN) has been the standard by which all undergraduate nursing programs are judged for program effectiveness. Consistent patterns of low pass rates can have serious implications for the academic institution, the nursing program, the nursing faculty, the program graduates, and the community at large. Preparing undergraduate nursing students for licensure is a major concern for undergraduate nursing faculty. Present pass rates for the graduate nursing baccalaureate students at a state university are currently below the national average. To address this problem, these researchers have identified interventions that predict success on the NCLEX-RN examination. The implementation of a five week online NCLEX-RN review course in conjunction with three workshops taught and designed by these researchers is used to increase the pass rate on the NCLEX-RN exam. The goal of the implementation of this assessment project is to provide the nursing student with the necessary tools to be successful on the NCLEX-RN. Furthermore, findings from this project have the potential to identify areas for the improvement in the nursing curriculum as well as the increase of the nursing program’s NCLEX-RN pass rate.
Book review: Unemployment in Africa: A psychological perspective
Annemarie Joannides
South African Journal of Industrial Psychology , 2005, DOI: 10.4102/sajip.v31i1.181
Abstract: Authors: Webster Gonzo and Ilse Elisabeth Plattner Publishers: University of Namibia Press Year: 2003 Reviewed For: South African Journal of Industrial Psychology Unemployment in an African country is a concisely written and well-structured book, which investigates the psychological impact of unemployment on Namibia’s ‘street unemployed’. This term refers to the large population of men who wait alongside the roads and at traffic intersections, in the hope of being offered causal employment. Essentially the books seeks to understand and evaluate the psychological experience of these men, in relation to several theoretical perspectives and with regards to the investigative research that was carried out by the authors.
Book review: Unemployment in Africa: A psychological perspective
Annemarie Joannides
South African Journal of Industrial Psychology , 2005, DOI: 10.4102/sajip.v31i2.192
Abstract: Title: Unemployment In an African country: a psychological perspective By: Webster Gonzo and Ilse Elisabeth Plattner Publishers: University of Namibia Press, 2003 Unemployment in an African country is a concisely written and well-structured book, which investigates the psychological impact of unemployment on Namibia’s ‘street unemployed’. This term refers to the large population of men who wait alongside the roads and at traffic intersections, in the hope of being offered causal employment. Essentially the books seeks to understand and evaluate the psychological experience of these men, in relation to several theoretical perspectives and with regards to the investigative research that was carried out by the authors.
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